fixed mixin call matching for multi-selector parent...
a few minor selector match fixes...
a few minor selector match fixes: updated tests.
Merge branch 'selector-match-fixes' of https://github.com/seven-phases-max/less.js
Change lessc exit status code on error. Fixes #1637
Add lessc parameter availability check. Fixes #1637

Conflicts:

	bin/lessc
Disable yui-compress parmeter (instead of falling back to incompatible clean-css). Fixes #1637
add options to disable clean css options that interfere with less operation. upgrade clean css
warn about using sourcemap option with clean css