Carousel: Use the transition duration from CSS

This makes it possible to change the transition duration in CSS
enable CSS source maps in grunt-contrib-less
Require comma on left side
Fix handling of btn-group placed inside input-group-btn (used for mixing dropdowns with normal buttons)
Downgrade Safari and OS X
Merge pull request #11916 from ZDroid/fix-iversions

Downgrade Safari and OS X
Merge pull request #11910 from InWayOpenSource/btn-group-inside-input-group-btn

Fix handling of .btn-group placed inside .input-group-btn
fix href of "Browser and device support"
Merge pull request #11923 from wangsai/fix-id

fix href of "Browser and device support"
fixes #11925: cover template for firefox
Merge branch 'master' of github.com:twbs/bootstrap
add inline note about navbar sizing
Fixes #11899: Ensure proper margins and .small/small usage for heading tags (e.g., .h1-.h6)
Merge branch 'master' into css-source-maps

Conflicts:
	Gruntfile.js
add source maps
fix typo
Merge pull request #11804 from twbs/css-source-maps

enable CSS source maps in grunt-contrib-less
Merge pull request #11881 from ZDroid/patch-1

Require comma on left side
Revert commits

Bootstrap is being relicensed from Apache 2.0 to MIT so that more of our community can use the free and open source software we lovely create together. As commits are copyright their original authors, the commits of any individual not agreeing to relicense their contributions are being removed to be later rewritten by the @twbs/team.

This undoes the changes introduced by the following commits:
https://github.com/twbs/bootstrap/commit/7ea34ae0ef79c793e9a9d393b4eef825b71e84b5 , https://github.com/twbs/bootstrap/commit/7376eef378fe7d5e69b8b8cce93c7c64b751d55a , https://github.com/twbs/bootstrap/commit/303ba1326bbe367598ab4cc063b4607507208e56 , https://github.com/twbs/bootstrap/commit/7d1c8c2a0ce16331583a965821690f7715e62908 , https://github.com/twbs/bootstrap/commit/11319f6da9f9a19ec40743cdfe868ac732698149 , https://github.com/twbs/bootstrap/commit/110fc8860117d8675345806219ba313b18086db2 , https://github.com/twbs/bootstrap/commit/ced08f69359f3a70771804a98fa3c499f388cc74
Merge pull request #11927 from twbs/revert_commits

Revert commits