CSS Stacker and Compressor: Compact several CSS files into a single file

This class can be used to compact several CSS files into a single file.

It can take several CSS files and generate a single file by concatenating all files after having stripped any white-spaces.

The class can serve the resulting CSS file as the current script output.

The CSS may be compressed with GZIP. If the original files were not modified, the class may return HTTP status 304 to make the browser use a cached version and prevent serving a file that was not changed.