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
Add nested kbd element styles for actual keys or inputs
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).
#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.
Fixed navbar radius of example at docs
fixes https://github.com/twbs/bootstrap/issues/13367

Second color stop value should be percentage instead of decimal value.
Update JSZip to v2.2.1.
Update holder.js to v2.3.2.
Run `grunt`.
Update type.less

For better readability on mobile devices
Remove sr-only from components/dropdowns example

Assuming sr-only is used in the actual live code so that the menu can be
shown open already ... but having sr-only in the highlighted example
code itself is confusing/misleading.

Also, change the text for the button from "Dropdown" to "Dropdown
trigger" for clarity (and it then matches
http://getbootstrap.com/javascript/#dropdowns)
Changed last-child to first-child
As noted by @jerem the first child will actually be the last shown
Update alert.js

Added call to remove() after event fires to clean up data as per discussion at #12379
Merge pull request #13424 from twbs/docs-libs

Update docs libs
Merge pull request #13437 from saas786/master

fixes #13367