fstandaert

On the efficiency of CArray.of_list and a potential Bigarray version, I think that an additional binding to SDL_RenderGeometryRaw (https://wiki.libsdl.org/SDL2/SDL_RenderGeometryRaw) would make more sense. It is similar to SDL_RenderGeometry, but only...

Sorry for the delay. I have implemented `SDL_RenderGeometryRaw` and new module `Color_ba` for bigarrays representing `SDL_Color`. Corresponding tests are also included. I am still unsure about the details for this...