Windows:
* OpenGL functions are now loaded dynamically.
Linux:
* Static linking of SDL is disabled because it causes problems on Ubuntu 10.10 RC.
Wii:
* Modularized the video backend so that it's independent from the engine.
* Restructuring and optimization of video code.
* Added brightness/gamma correction using the TEV unit that works in all color modes (and it's fast!)
OpenGL:
* Moved code to a separate file, opengl.c.
* Added brightness/gamma correction using GLSL that works in all color modes (confirmed to work but not yet used by the engine)
* Added support for 8-bit indexed textures using GLSL, disabled for now because it causes problems in conjunction with bilinear filtering.
* Lots of other changes that I don't remember.
