Only enable `pause: hover` for non-touch browsers

Fixes #11967.
Chromium bug #337668 seems to have been fixed.
Added default collapsed class to the collapsed accordion examples in the docs
Added default collapsed class to the collapsed accordion html code example in the docs
Merge pull request #14709 from twbs/add-collapsed-default-class-to-accordion-toggle-example

Added default collapsed class to accordion
Chromium bug #282918 seems to have been fixed.
Chromium bug #329574 seems to have been fixed
Filed WebKit bug for #8350
grunt
Update grunt-contrib-jade version
Merge pull request #14715 from watilde/update/grunt-contrib-jade

Update grunt-contrib-jade@0.13.0
Fix #12563: Reiterate that empty tooltips+popovers do not get displayed
Merge pull request #14716 from blankmaker/docs/fix-12563

Fix #12563: Elaborate that popover('show') checks title/content
Merge pull request #14626 from twbs/carousel-pause-hover-non-mobile

Only enable `pause: hover` for non-touch browsers
fixes #14714: don't use specific value in buttons docs
Merge branch 'master' of github.com:twbs/bootstrap
Add `keyboard` option to carousel

Also adds unit tests for keyboard events.

Fixes #14468.
grunt
Escape key should only close Dropdown
Fixes #14711: Account for list groups in collapsing panels