OpenGL: Public flatsprite: The Fixening

Merged next into public_flatsprite so that the latest OpenGL changes are merged into it and fixed the conflict with the new sprite projection. Also, have fixed the issues with A0 sprites flipping when looked at the wrong way, which may or may not have been an issue before.

NOTE: I assume so many files changed is because of me merging next into this branch. The only file worth noting that changed was hw_main.c