Cache buster for url tokens
Renamed --cache-buster option to --url-args
improved multiple `default()` guards conflict detection, updated tests.
Split rhino and rhino version of lessc.  This lets us have cleaner tests (since we don't need to include the test code in the rhino source).  Also
sets the stage for sharing lessc code between lessc and rhino less (issue #14) and provides a hook so lesscss-java can have custom js.
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
Updates bower.json for current version, relates to #1628
Merge pull request #1828 from ruyadorno/iss-1628

Updates bower.json for current version
Merge branch 'rhino-lessc' of https://github.com/dhaber/less.js into dhaber-rhino-lessc