Merge pull request #12378 from andrewdisley/patch-1

Fix #10348: Customizer dependencies
disable IE11 in BrowserStack config due to frequent timeouts
README: use Bootstrap v3-specific StackOverflow tag
update to iOS v7 in Sauce test config
Merge pull request #12386 from twbs/update-iphone

update to iOS v7 in Sauce test config
re-enable OS X Chrome in Sauce tests
Merge pull request #12387 from twbs/osx-chrome

re-enable OS X Chrome in Sauce tests
fixes #10495 by forcing .navbar-brand height to prevent it's inner content from increasing navbar height
fix #12261
mark .box-shadow() mixin as deprecated; fixes #12396
docs & comments: v3.1 => v3.1.0
Merge pull request #12398 from twbs/deprecate-box-shadow-mixin

mark .box-shadow() mixin as deprecated
Merge pull request #12315 from twbs/use-shrinkwrap

Do npm caching based on npm-shrinkwrap.canonical.json
Change positioning reference from left to right in affix's example.
Merge pull request #12403 from Quy/master

Change positioning reference from left to right in affix's example.
document id requirement in carousels per #12393
Merge branch 'master' of github.com:twbs/bootstrap
Upgrade to Normalize v3-rc1 in prep for v3 final
Remove optgroup resets from #7611 since Normalize fixes those upstream
Remove #8350's reset for number inputs since Normalize fixes those upstream