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`.
fixes #11099 - $.collapse() overrides the original dimension of the coll...
fixes #13296 Dropdown disappears with right-click on Firefox
fix #13360 by making deprecation notices visible in customizer
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
quote attribute value in selector in offcanvas.js
quote attribute value in selector in JS docs example
quote attribute values in selectors in JS unit tests for consistency
rename jquery.js -> jquery.min.js since it's minified
Merge pull request #13381 from twbs/vendor-jquery-min

rename jquery.js -> jquery.min.js since it's minified
quote attribute value in ^= selector in button.js
Merge pull request #13354 from twbs/fat-13296

fixes #13296 Dropdown disappears with right-click on Firefox
Merge pull request #13306 from twbs/fat-11099

fixes #11099 - $.collapse() overrides the original dimension of the coll...
Update composer.json

Update minor version of alias to proper.
Merge pull request #13385 from vnagara/patch-1

Update composer.json
move call for removeBackdrop() to backdrop()

Closes #11958 by rebasing & merging it