Fixes #146 - moves benchmark out of the repository.

* Updates clean-css tagline to include a link to css-minification-benchmark.
Updates unit tests to allow flat arguments only in cssContext.

* There is no ' #<number>' appended to test name anymore.
Renames test/custom-test.js to test/module-test.js.
Version 2.0.0.
Add bin/cleancss to the JSHint command and fix the warnings.
Update JSHint's options.

Enable indent option and move multistr option where is needed only.
Style change: use a space for anonymous funtions.