Remove all calls to SDL's "render" subsystem.
Remove all calls to SDL's "render" subsystem.

SDL provides an abstraction for 2D graphics, but it's quirky and
incomplete (No way to draw rotated images or set a clipping rectangle,
weird heavy-weight textures...). Every platform we'll be deploying on has
OpenGL anyways, so let's just continue using that and enjoy the benefits
of more available features later.

aduros/amity,aduros/amity,aduros/amity,aduros/amity,aduros/amity,aduros/amity,aduros/amity