Revert "Images are responsive by default"

This reverts commit d29f851e827db27fb42573f14003bb018c037342.

Making <img>s responsive by-default without opt-in can severely break
third-party widgets such as Google Maps.
This was an acknowledged problem in Bootstrap v2
(see https://github.com/twbs/bootstrap/issues/1506 ) and was fixed in v3
by requiring the .img-responsive class for explicit opt-in
(see 09cdee2f03aaad5c5a767fbec2e3896ad3d1f980).
The situation hasn't really changed since then. The responsive-by-default
approach hasn't become any more suitable in the intervening time.

So let's avoid having this regress in v4. :-)

more migration content

start to fill in more migration docs

grunt css

update image docs and styles

Images are responsive by default

grunt css

better tables in the docs

simplify grunt compiling docs

comment out download options for now

simplify js docs overview section

scope the anchor highlighting

fix page layout for examples overview

more component alignment fixes for docs

copy change

fix alignment of progress elements in examples

nuke theme toggler js

typo

input groups subnav

input groups: drop the tooltips warning, move accessibility notice to a sub section

simplify input group docs to remove two notices, condense some language

remove justified button groups

fix examples alignment

remove all customizer comments from variables file

grunt action

nuke those for now

docs redesign a bit

Remove dupe docs CSS, move anchor styles to scss directory, recompile

fix validation, run grunt dist

Merge branch 'master' into v4

Conflicts:
.travis.yml
Gruntfile.js
bower.json
dist/css/bootstrap.css
dist/css/bootstrap.css.map
dist/css/bootstrap.min.css
dist/js/bootstrap.js
dist/js/bootstrap.min.js
docs/_data/glyphicons.yml
docs/_includes/components/breadcrumbs.html
docs/_includes/components/button-dropdowns.html
docs/_includes/components/button-groups.html
docs/_includes/components/dropdowns.html
docs/_includes/components/glyphicons.html
docs/_includes/components/labels.html
docs/_includes/components/list-group.html
docs/_includes/components/media.html
docs/_includes/components/navs.html
docs/_includes/components/panels.html
docs/_includes/components/progress-bars.html
docs/_includes/components/thumbnails.html
docs/_includes/components/wells.html
docs/_includes/css/buttons.html
docs/_includes/css/forms.html
docs/_includes/css/helpers.html
docs/_includes/css/images.html
docs/_includes/css/less.html
docs/_includes/customizer-variables.html
docs/_includes/getting-started/accessibility.html
docs/_includes/getting-started/browser-device-support.html
docs/_includes/getting-started/community.html
docs/_includes/getting-started/examples.html
docs/_includes/getting-started/grunt.html
docs/_includes/getting-started/license.html
docs/_includes/getting-started/template.html
docs/_includes/header.html
docs/_includes/js/affix.html
docs/_includes/js/alerts.html
docs/_includes/js/carousel.html
docs/_includes/js/collapse.html
docs/_includes/js/dropdowns.html
docs/_includes/js/modal.html
docs/_includes/js/overview.html
docs/_includes/js/popovers.html
docs/_includes/js/scrollspy.html
docs/_includes/js/tabs.html
docs/_includes/js/tooltips.html
docs/_includes/js/transitions.html
docs/_includes/nav/javascript.html
docs/_layouts/default.html
docs/assets/css/docs.min.css
docs/assets/css/src/docs.css
docs/assets/js/customize.min.js
docs/assets/js/docs.min.js
docs/assets/js/raw-files.min.js
docs/assets/js/vendor/FileSaver.js
docs/assets/js/vendor/autoprefixer.js
docs/assets/js/vendor/uglify.min.js
docs/dist/css/bootstrap.css
docs/dist/css/bootstrap.css.map
docs/dist/css/bootstrap.min.css
docs/dist/js/bootstrap.min.js
docs/examples/blog/index.html
docs/examples/carousel/index.html
docs/examples/cover/index.html
docs/examples/dashboard/index.html
docs/examples/narrow-jumbotron/narrow-jumbotron.css
docs/examples/navbar-fixed-top/index.html
docs/examples/navbar-static-top/index.html
docs/examples/non-responsive/index.html
docs/examples/non-responsive/non-responsive.css
docs/examples/theme/index.html
grunt/configBridge.json
js/affix.js
js/carousel.js
js/collapse.js
js/dropdown.js
js/modal.js
js/popover.js
js/scrollspy.js
js/tab.js
js/tests/unit/affix.js
js/tests/unit/button.js
js/tests/unit/carousel.js
js/tests/unit/modal.js
js/tests/unit/tooltip.js
js/tooltip.js
less/badges.less
less/glyphicons.less
less/type.less
less/variables.less
package.json
scss/_dropdown.scss
scss/_forms.scss
test-infra/npm-shrinkwrap.json

Merge pull request #15954 from twbs/sauce-hidepassed

Use different way to make failing test more visible in Sauce

Use different way to make failing test more visible in Sauce

Merge pull request #15929 from kkirsche/patch-5

[Fixes #15928] Encourage use of icons with form validation states for co...

[Fixes #15928] Encourage use of icons with form validation states for colorblind users

[Fixes #15928] Encourage use of icons with form validation states for colorblind users

Update text per @patrickhlauke's feedback

Update text per @patrickhlauke's feedback.

Fix stupid grammar mistake

Merge pull request #96 from twbs/gem-badge

Add Ruby Gem badge to README

automatic grunt dist

Merge pull request #15826 from kkirsche/patch-19

[Fixes #15825] .initialism class should use mixin

automatic grunt dist

Merge pull request #15941 from twbs/ijcheung-collapse-update-all-triggers

Update all collapse triggers with .collapsed class and aria-expanded

Update all collapse triggers with .collapsed class and aria-expanded

Fixes #15741
Closes #15751 by merging it.

automatic grunt dist

Run `grunt`.

Merge pull request #15933 from twbs/qunit-module-hooks

Unit tests: Use new names of module hooks

QUnit.jsDump => QUnit.dump

Refs http://qunitjs.com/upgrade-guide-2.x/#replace-qunit-jsdump-with-qunit-dump

Use QUnit.log(...) instead of QUnit.log = ...

Refs http://qunitjs.com/upgrade-guide-2.x/#replace-qunit-log-callback-with-qunit-log-callback-for-all-reporting-callbacks

automatic grunt dist

Unit tests: Use new names of module hooks

Refs #15893

Merge pull request #15930 from twbs/modal-restore-inline-padding

Modal: Apply any preexisting body padding again after closing

Modal: Apply any preexisting body padding again after closing

Prevent collapsed navbar in Non-responsive Example

Closes #15291 by merging it.

automatic grunt dist

Tooltip: Avoid creating an unnecessary tooltip when `Tooltip#hide` is called

Fixed performance bug where a tooltip element is created and then immediately destroyed when tooltip.hide() is called and there is no existing tooltip element

Resolves #15557 by merging it.

automatic grunt dist

Dropdowns: Skip `.disabled` instead of `.divider` on keydown event

Fixes #15147.
Closes #15520 by merging it.

automatic grunt dist

Merge pull request #15923 from kkirsche/useExplicitVariableDeclaration

[Ref #15881] Use Explicit JS Variable Declarations rather than Chained

automatic grunt dist

Merge pull request #15693 from huang-x-h/patch-1

tip method in popover.js can be removed

[Ref #15881] Use Explicit Values rather than Chain

[Ref #15881] Use Explicit Values for javascript variables rather than chained ones.

From https://github.com/twbs/bootstrap/pull/15881#discussion_r25330647

fix 2 typos in modal unit test assertion messages

Merge pull request #15916 from kkirsche/patch-2

Add source code documentation of justified navbar for #15906

Merge pull request #15914 from StevenBlack/docs.js.headings

docs > js > headings

Document justified navbar for #15906

Document in the source code that the justified nav is meant for single line list items only. This should help prevent Issues like #15906 in the future.

Follow-up to 769c27a19f: Add new section to nav

Document how to properly handle modals with dynamic content height

Fixes #15106.
Closes #15910.

Dropdown unit tests: Tiny style changes

Accessibility changes to headings (transitions.html)

Accessibility changes to headings (overview.html)

automatic grunt dist

Merge pull request #15913 from twbs/scrollspy-consistency

ScrollSpy: Small style consistency adjustments

Merge branch 'master' of github.com:twbs/bootstrap

Fix #15911: Clear the floats and move the padding to the header

ScrollSpy: Small style consistency adjustments

Merge pull request #98 from twbs/sync-package

Sync package.json with v3

Merge pull request #15900 from kkirsche/patch-5

[Docs—Fixes #15882]Use an ID as the example for Scrollspy

Merge pull request #15903 from michael-k/patch-1

Updated license links

Merge pull request #15887 from StevenBlack/headings-labels

docs>components>labels headings

Merge pull request #15889 from StevenBlack/headings-progressbars

docs>components>progress bars headings

Merge pull request #15828 from kkirsche/patch-20

Add plugin package keyword recommendation

Merge pull request #15891 from StevenBlack/headings-listgroup-panel-well

docs>components>(remaining components) headings

Merge pull request #15890 from StevenBlack/headings-media

docs>components>media object headings

Merge pull request #15888 from StevenBlack/headings-thumbnails

docs>components>thumbnails headings

Merge pull request #15886 from StevenBlack/headings-buttondropdowns

docs>components>button-dropdowns headings

Merge pull request #15885 from StevenBlack/headings-buttongroups

docs>components>button-groups headings

Merge pull request #15884 from StevenBlack/headings-dropdowns

docs>components>dropdowns.html headings

Merge pull request #15908 from kkirsche/bumpMarkdownIt

Bump markdown-it to ^3.0.7

Sync package.json with a1fd86cdf9dca0f0d11ae895a92debe6a05b1163

Add Ruby Gem badge to README

Merge pull request #94 from twbs/jscs-gruntfile

Exempt Closure part of Gruntfile from requireCamelCaseOrUpperCaseIdentifiers

Merge pull request #15907 from twbs/time-grunt

bump time-grunt to ^1.1.0

Bump markdown it to 3.0.7

Bump markdown it to 3.0.7

3.0.7 / 2015-02-22

Match table columns count by header.
Added basic CLI support.
Added \v \f to valid whitespaces.
Use external package for unicode data (punctuation).

bump time-grunt to ^1.1.0

Merge pull request #15904 from kkirsche/patch-8

Closes #15904

Add unit test of aria-expanded to dropdown suite

Redo of #15876

Merge pull request #15905 from kkirsche/modalAriaTests

Add unit tests for aria-hidden to modal suite

Add tests for aria-hidden of modal

Add tests for `aria-hidden` of modal

Use strictEqual of 1 here instead of 2 asserts

Merge pull request #15893 from twbs/qunit-modern

Modernize QUnit usage by avoiding usage of global functions

Updated license links

Added attributes rel and target.

[Docs—Fixes #15882]Use an ID as the example for Scrollspy

Fixes #15882 — Use an ID as the example for Scrollspy so that it is more clear that this is for use with a single nav.

Merge pull request #15898 from coliff/patch-3

Change CC link in footer to HTTPS