Travis GitHub Releases (#2552)

Travis GitHub Releases (#2552)

* Make Travis to deploy built files for tags

See https://docs.travis-ci.com/user/deployment/releases

* Remove and ignore dist/* files

Travis now builds and deploys these files for all tags, so we don't need to have them on the repository anymore.

* Add download links to the latest version

Remove outdated *standard build* and *bundled with Moment.js* links from the documentation and add a link to the latest GitHub release, from where the user can download `*.js` files.