Customizer: switch to UglifyJS2 (v2.4.13).

The uglify build is generated with `uglifyjs --self -o uglify.min.js`.
Add the jquery check in customizer's output.
Add the license header in the non minified build too.
Run `grunt`.
Wait for the expected target during a collapse

Actually wait for the collapsed item to complete. If complete is called
with other target, instead of simply returning and do nothing, wait again
until the proper target triggers the event (otherwise this leaves collapse
in a broken state).
rm not particularly useful @zindex var comments
fix #13340 by documenting @icon-font-path & @icon-font-name more
Merge pull request #13353 from twbs/fix-13340

Document @icon-font-path & @icon-font-name more
fixes #11099 - $.collapse() overrides the original dimension of the coll...
Merge pull request #13330 from Kronuz/patch-1

Wait for the expected target during a collapse
fixes #13296 Dropdown disappears with right-click on Firefox
Added specificity note to docs per issue #13332
Fixed typo and added leading space
grunt dist
fixes #13365: remove dupe css in grid example
Merge pull request #13358 from Jakobovski/docs-improvements-#13332

Added specificity note to docs per issue #13332
fix #13360 by making deprecation notices visible in customizer
fix #13337 by mentioning removal of .progress-* contextual classes
quote data-* attribute value in docs JS per best-practices
Merge pull request #13373 from twbs/fix-13360

Make variable deprecation notices visible in customizer