Assets (images, audio) must be exported to a meaningful format

[Greenlock]

Game assets are stored in various Unity binary files and need to be exported to file formats that can be edited. I believe images are stored as DirectDraw Surfaces (.dds), so those should be exported into separate files, for example. The UBML builder already exports into a directory for this purpose. Also, object data that is put in another file should be somehow excluded from the UBML and explicitly linked to in the markup.