Fixed nested tab elements li activation

Added closest li instead of direct parent so that you can nest multiple elements within tabs, such as button groups
Fix form-control-feedback position when label has sr-only class
Fix indent
added bower reference to main less file
Add documentation for using optional icons with sr-only labels
Dropdown menu in justified button-group

It seems that dropdown-menu in justified button-group appears at the far
left of the group. Check the problem in [Bootstrap
site](http://getbootstrap.com/components/#btn-groups-justified).
FIX: #13355. Added .navbar-nav to migration change list.
add IE10 viewport bug workaround to examples

Closes #13379.
add unit tests for Carousel slid events
document that non-:visible scrollspy targets are ignored; fixes #13394
fixes #13157 - Collapse plugin - issues with transition end event bubbling
#11464 - Fix JS noConflict mode - Refactor all plugins to use an internal reference to the jQuery plugin, because in noConflict mode you can never expect to be defined on the jQuery object
fires closed.bs.alert *after* DOM detach()

fires closed.bs.alert *after* element is removed from DOM.
Previously it fired while the element was still attached.
the master branch is the relevant one for current build status
README: Authors => Creators
Merge pull request #13397 from twbs/fix-13394

document that non-:visible scrollspy targets are ignored
document that show-ing a tooltip/popover on a hidden element doesn't work; fixes #13362
Merge pull request #13374 from Jakobovski/fix-issue-#13355

FIX: #13355. Added .navbar-nav to migration change list.
Merge pull request #13390 from twbs/ie10-viewport-bug

add IE10 viewport bug workaround to examples
Merge pull request #13176 from twbs/fat-13157

fixes #13157 - Collapse plugin - issues with transition end event bubbli...