changed: GetSrcPixelTypeAndFormat()

Returns GL_BGRA instead of GL_RGBA for RGBA textures.
Always considers textures with 32 bpp as having the color type FIC_RGBALPHA.

Also added an error check in CGLTextureResource::CreateFromDesc().
updated: GetNextImageFileNumber()
updated: TextureRenderTargetTest
changed: GetSrcPixelTypeAndFormat()

Decides the color format (GL_RGBA or GL_BGRA) based on whether the texture is used as a render target or not.
updated: CGLLockedTexture
updated: GLGraphicsResources.cpp