Clarify that the focus docs styles are not in the repo, per https://github.com/twbs/bootstrap-sass/issues/497
rm outdated `<select>` references from comments in forms.less
document #11675
use height adjectives for greater clarity
docs mention for #12188
refer to correct component
Fixes #12171: Ensure panel groups have a bottom margin since we nuke it on child panels
Merge branch 'master' of github.com:twbs/bootstrap
Don't test Linux browsers since we don't support them officially and they're failing our tests
Update docs per `.container-fluid` addition
- Remove `.container-fluid` from "removed classes".
- Container isn't fluid by default (`.container`) and `.row` isn't percentage-based, so update docs.
Merge pull request #12193 from ZDroid/migration

Update docs per `.container-fluid` addition
Merge branch 'minify-assets' of https://github.com/XhmikosR/bootstrap into XhmikosR-minify-assets

Conflicts:
	package.json
grunt dist
Merge branch 'master' of github.com:twbs/bootstrap
rm lingering reference to Recess in the docs

Refs c0200426ee72b165de400db740a60bae5d344b3c
Merge branch 'master' into docs_derp

Conflicts:
	docs/getting-started.html
homepage improvements
brand guidelines cleanup
Improve spacing and alignment of sections and their headings
Formatting and docs changes