Removed an incorrectly placed comma in the .info files of the starterkits. Thanks to achton for finding it

Added the posibility to attach files to your responsive grids for overriding your default CSS based on the currently active responsive grid

Major changes to the .info array for css support. Also added library support for adding js and css in a bulk. Added caching to the css and library registry. Added a default styles.css to every starterkit.

Added mobile.css to starterkits and renamed the keys of the optional css files and grids in the base themes (alpha & omega) with preceding omega_ / alpha_ so that we dont steal the namespace from the subthemes. / General cleanup.