dofu

Now this patch is being intensively used by Python-SoXR and seems like working fine. I'm maintaing libsoxr in my personal repository. https://github.com/dofuuz/soxr/

In system that 'unsigned long' is 32-bit(i.e. Windows, 32-bit Linux), dithering is not working as expected. In those systems, dithering has pattern of every 16 samples. Later 8 samples are always ±0. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 -1 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 -1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1...