* This commit aims to both continue the rasterizer cache cleanup by
separating CachedSurface into a dedicated header and to start weeding
out the raw OpenGL code from the cache.
* The latter is achieved by abstracting most texture operations in a new
class called TextureRuntime. This has many benefits such as making it easier
to port the functionality to other graphics APIs and the removal of the need
to pass (read/draw) framebuffer handles everywhere. The filterer and
reinterpreter get their own sets of FBOs due to this, something that
might be a performance win since it reduces the state switching
overhead on the runtime FBOs.
