Okay so WindowsWrapper.h now just includes Windows.h if it wants
non-portability. This meant I had to split the custom RECT struct
back to the original RECT and unknown nameless struct (one uses
left/right, while the other uses front/back).
Along with being more accurate to the original, this fixes switching out
of fullscreen causing textures to disappear. This was caused by DirectX
destroying textures that are marked as render-targets when a device-loss
occurs. SDL2 doesn't do anything to recover them, unlike regular
textures, so my solution is just to avoid render-target textures
entirely.
On the upside, this should make drawing text to surfaces much faster,
since we're not reading back bitmaps from the GPU.
