Remove default_size_tile_atlas.

I was sure I removed this in my SDL2 refactor, but I guess not. This is
causing a massive memory leak every time we switch tileset, let's just
get rid of it.
Remove duplicate behavior.

Just a small optimziation as well.
Merge removal of now unneded roration cache infrastructure.
Style change I forgot to add to previous merge.
Remove useless warning supressors that have no effect on c++ code.