CL_Sprite_Impl::create_textures patch

[Trigve]

Hi,

this patch create textures with sizes equal to description_frame.rect (aligned to nearest power of 2)

[Magnus Norddahl]

This patch creates an extra pixel buffer - why does it do that?

Creating a power-of-two texture does not require a complete upload of all pixels of the texture. set_subimage uploads to only a portion of a texture and should work on all versions of OpenGL (afaik).