Add support for lessOptions.
Fix less options test.
Add Promise and System to jshint globals.

Sublime text won't stop complaining about that.
Use a flat object to set less options.

This change removes lessOptions.parse and lessOptions.eval. Thanks to
@stevenchacon for pointing out that we don't need to separate those
options, yay!
Fix test after rebase.
Document System.config.lessOptions.
Merge pull request #210 from bitovi/less-options

Add support for lessOptions.