Update requirejs to compatible version, remove r.js

Conflicts:
	package.json
Remove comment
Fixes #14450. Remove CommonJS+AMD syntax.

- To keep file size unaffected, an extra pragma was added to build.js to remove certain lines when building with special comments.

Conflicts:
	src/core.js
	src/css.js
	src/effects.js
	src/event.js
	src/manipulation.js
	src/offset.js
Fix #14432: Always return string from .css("z-index"). Close gh-1395.
(cherry picked from commit 5ce4b06c285bd8cf52eaff0f39e0b9192a927873)

Conflicts:

	src/css/curCSS.js
No ticket: Small curCSS size optimizations
(cherry picked from commit a339096d6a9d0313c2184de0d626e2c7e127955b)

Conflicts:

	src/css/curCSS.js
No ticket: Test cleanup
(cherry picked from commit 8df348e9eb3681ff5f09b1e52b72573e2eee3105)

Conflicts:

	test/unit/css.js
Fix #14394: Changing style !important in webkit. Close gh-1385.
(cherry picked from commit 24e587929f62428e1959b10aace6dc4fd65ab397)

Conflicts:

	src/css.js
No ticket: Clean up uglifyjs compress options. Close gh-1382.