Added case insensitive units handling. Issue #2096
Merge https://github.com/less/less.js into case-insensite-units-2096

Conflicts:
	test/css/comments.css
	test/less/comments.less
Merge pull request #2181 from SomMeri/case-insensite-units-2096

Case insensitive units parsing and comparison
Merge https://github.com/less/less.js into rhino