Remove `.modal-open` class after backdrop is hidden

Fixes #14274.
Fixes #14632.
grunt
Fixes #14642: Add docs mention for blank checkboxes and radios
grunt
Fixes #14592: Add new variable for progress border radius
grunt
the justified nav bug is still present in Safari v7.1
Remove Safari percent rounding bug entry from Wall of browser bugs

Bug is fixed in OS X Safari v7.1
Refs #14663
Remove #8702 entry from Wall of browser bugs

A fix is shipping in Firefox 35: https://bugzilla.mozilla.org/show_bug.cgi?id=763671
Merge pull request #14570 from twbs/remove-modal-open-after-backdrop-closed

Remove `.modal-open` class after backdrop is hidden
grunt
document S3Cachefile.json
Safari percentages were fixed in v7.1 & iOS 8.0; fixes #14663
Merge pull request #14666 from twbs/fix-14663

Update docs to reflect that Safari percentages were fixed in v7.1 & iOS 8.0
Fixes #14227, #14603: Drop translate3d for translate on navbars to avoid iOS rendering problems and ensure a more predictable base styling
Merge branch 'master' into remove_translate3d
grunt
Merge pull request #14667 from twbs/remove_translate3d

Remove translate3d
fixes #14654: callout for scrollspy-nav link
Reverts 0ec05da0eea03849fc72bed84a2c7fe7be1de1b6 to bring back #14444 to fix #14348 (again)