Start calling FreeImage
Start calling FreeImage to do stuff. Also, haul ddg-build back; the versioning between two git repos was a source of mistakes.
Refactor some FreeImage code to make the FREE_IMAGE_FORMAT enum stable. Also cahnge some difficult to read code.
Intermediate checkin: add a lot of code to the content builder to handle texture options.
Use class attributes for enums rather than variables.
Fix texture description iteration.
Clean up the data representation by moving some things to member variables.