Cache buster for url tokens
Renamed --cache-buster option to --url-args
improved multiple `default()` guards conflict detection, updated tests.
Normalize require-calls for Browserify
Merge pull request #1822 from pateketrueke/static-require-calls

Normalize require-calls for Browserify
Merge pull request #1823 from seven-phases-max/mixin-guard-default-2

Improved multiple `default()` guards conflict detection.
Merge branch 'cache-buster' of https://github.com/bcluca/less.js

Conflicts:
	test/index.js