Allow for luminance upload
Allow for luminance upload

its hard coded to types and since pixelFormat directly maps to types including I believe my proposed addition of luminance, it needs to allow for all types. I am using luminance successfully with this approach. I am basically passing in a binary mask and RGB is overkill

These types must all have support:
GPUPixelFormatBGRA = GL_BGRA,
GPUPixelFormatRGBA = GL_RGBA,
GPUPixelFormatRGB = GL_RGB,
GPUPixelFormatLuminance = GL_LUMINANCE
jakeva/GPUImage,lacyrhoades/GPUImage,eighteight/GPUImage,lacyrhoades/GPUImage,shi-yan/GPUImage,shi-yan/GPUImage,birthmark/GPUImage,eighteight/GPUImage,wfxiang08/GPUImage,BradLarson/GPUImage,birthmark/GPUImage,wysaid/GPUImage,PlanetaToBe/GPUImage,BradLarson/GPUImage,wfxiang08/GPUImage,UndaApp/GPUImage,BradLarson/GPUImage,PlanetaToBe/GPUImage,UndaApp/GPUImage,jakeva/GPUImage,wysaid/GPUImage,wysaid/GPUImage,eighteight/GPUImage