Merge pull request #16 from sulix/master

SDL_LoadBMP and colour mouse cursors working
SDL2_image implemented. Pretty small without RWops.
SDL2_image fix, SDL2_ttf paaart oooone
SDL2_ttf done. Unless someone cares about RWops.
SDL2_mixer mostly implemented, need to do Special Effects API.
SDL2_mixer first draft is done.
The nativeLibName can/should be private.
Does C# really have both string and String?
Removed SDL2_net. Just use Lidgren.Network instead.
Remove 2 from class names to prevent namespace ambiguity.
Fix parameter for CreateWindowAndRenderer.
Update README to address SDL2#'s coding style.
Durr, that is a macro, flibit.
SDL_joystick written. SDL_gamecontroller is next.
SDL_gamecontroller.h done.
SDL_Log[Get|Set]OutputFunction
Fix endianness assumption, make PIXELFORMATs readonly.
These aren't that problematic, we just name them like we do IntPtrs.
For SDL2#, this will be const, not redefinable.
Checked on the ButtonBind struct, should be alright.