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