Fix issue #114 : XML files can be used as reusable packs of configured and connected filters to speed graph building.
File Open opens an XML file as a new graph. Every other operation with XML files should add the XML file to the existing graph.
Rename File/Open as File/Open graph/media file.
Combine File/Open and File/Render Media file into File/Add graph/media file.
Retain File/Render Media File to preserve old behaviour (allowing RenderFile on .XML or .GRF file)
Fix issue #84 : Add *.awb to audio media types in file open dialog.


git-svn-id: http://graph-studio-next.googlecode.com/svn/trunk@150 c2f33eb2-41b2-391d-4cb4-d9d0608729ba