Merge branch 'jc/spht'

Merge branch 'jc/spht'

* jc/spht:
  Use gitattributes to define per-path whitespace rule
  core.whitespace: documentation updates.
  builtin-apply: teach whitespace_rules
  builtin-apply: rename "whitespace" variables and fix styles
  core.whitespace: add test for diff whitespace error highlighting
  git-diff: complain about >=8 consecutive spaces in initial indent
  War on whitespace: first, a bit of retreat.

Conflicts:

	cache.h
	config.c
	diff.c