#85 Implement HQ2XS scaling filter

[André]

Being someone that records video games using emulators and so on, image quality is important. I've been using the HQ2X filter that ffdshow provides for a long time, however, it is not as good as the hq2xs variation of it, which provides sharper results (slight, but noticeable).

I'd like it if you implemented that scaling filter into ffdshow (which is most likely something you couldn't care less for, and I understand, but anyway, it doesn't hurt to ask). http://code.google.com/p/emu-1964/source/browse/src/1964Video/TextureFilters_hq2x.cpp?spec=svn77&r=77

[André]

The slight, but noticeable differences between the two filters.