CVPixelBuffer release
MTLTexture+CVPixelBuffer (#73) * add mtltexture to cvpixelbuffer conversion * update version to 0.11.6 * move extension to CVPixelFormat+MTLTexture.swift * remove unsused error type
MTLTexture+CVPixelBuffer (#73) * add mtltexture to cvpixelbuffer conversion * update version to 0.11.6 * move extension to CVPixelFormat+MTLTexture.swift * remove unsused error type