Switching internal image format to BGRA from RGBA

Switching all graphics systems and image formats to utilize BGRA
internally allowing less casting and faster load times, if you update to
this commit you will need to download the new plugin because it was
previously writing the image pixel data in RGBA format.

The purpose of utilizing this format internally is because this is what Direct3D and OpenGL and most x86 graphics hardware use, allowing more efficient and optimal load times.