fix #12154
Fix #12025 and minify styles
fix #12007 by clarifying target of dropdown events
refactored and renamed grid mixins
fixed first element padding of list-inline
rm callout about creating .container-fluid-alikes now that .container-fluid has been added
mv .img-responsive docs from Overview to Images section
Remove redundant :-moz-placeholder styles

No need for old Firefox versions support.
Improve alignment of the dashboard placeholder images
Fixes #12435
add note to CONTRIBUTING.md about `outline: none`
Tightening up popover arrow css scope to apply only to direct descendant arrows.
Allow the bootstrap package in npm to expose css and less
fixed two typos in carousel.less

carousel.less has two typos in glyphicon classnames. fixed them.
Remove comma first rule

Removes outdated coding style rule.
die tabs, die!
fix #12566
Add examples/**/*css in the csslint task.

Fixes #12457.
Examples: fix csslint errors.
fix #12494 in the migration docs
Merge pull request #12533 from 1000hz/tighten-popover-arrows-scope

Scope popover arrow css to direct descendant