Convert the simple filter to completely integer based processing..
Convert the simple filter to completely integer based processing..

There is still the vp8_simple_filter_mask, which is converting from
uint to uchar, because evidently my GPU doesn't know how to properly do
an absolute value with integers (hopefully a reboot fixes this).

awatry/libvpx.opencl,awatry/libvpx.opencl,awatry/libvpx.opencl,awatry/libvpx.opencl