Minify css with clean-css.
Add csslint support.
Drop grunt-recess for grunt-contrib-less & co
restore original options value
adding json
fixups to csscomb grunt task
merge, compile
derp, don't sort min /cc @cvrebert
single array == no rogue spaces
specify block indent as numeral to prevent fubared media query output
more closely align property order with recess
Merge branch 'master' into drop_recess_for_less

Conflicts:
	dist/css/bootstrap.min.css
Switch to `&:extend(.clearfix all)` for clearfix mixin

Original discussion:
https://github.com/less/less.js/issues/1437#issuecomment-21383639.

Since we’re switching to `grunt-contrib-less`, we can take advantage of
newer LESS features than what RECESS supported. Included in that is the
ability to `:extend`, and not only that, but `:extend(.mixin-name
all)`. By doing so, we remove duplicate CSS for all our elements that
were being clearfix-ed.

Fixes #8947, #8968, #8991, #9257, #9268, #9291, #9430, #9604, #9686,
#9929, #10731, #10793, #11305, #11498, #11533, #11570, #11604, #11652.

(dem issues, tho)
Merge branch 'pr/11778' into drop_recess_for_less

Conflicts:
	Gruntfile.js
	dist/css/bootstrap-theme.min.css
	dist/css/bootstrap.min.css
Merge branch 'pr/11779' into drop_recess_for_less

Conflicts:
	Gruntfile.js
	package.json
grunt
Undo merge of #11778 and use cleancss min option
Merge pull request #11790 from twbs/drop_recess_for_less

Drop grunt-recess for grunt-contrib-less
improve compliance with LESS's strictMath
Merge pull request #11807 from twbs/stricter-math

improve compliance with LESS's strictMath