Added handler for shutdown signals.
Added handler for shutdown signals.

Simplified functionality - now only accepts image filenames, not surfaces.

sparkslabs/kamaelia,sparkslabs/kamaelia,sparkslabs/kamaelia,sparkslabs/kamaelia,sparkslabs/kamaelia,sparkslabs/kamaelia,sparkslabs/kamaelia,sparkslabs/kamaelia,sparkslabs/kamaelia,sparkslabs/kamaelia