Added these objects that were lying around:
pix_contrast (also known as pix_saturation) adjusts contrast and saturation
pix_deinterlace does basic field averaging and a type of 'adaptive'
blending based on motion difference (using the non-discriptive 'mode
0/1' message).
Both of these are YUV only right now, but I will write the RGB version on Windows pretty soon.
cgc