imgproc: Added basic RGB skin detection filter

Hi,

I have added a very basic RGB skin detection filter to imgproc: it takes an ImageData as input and outputs a O/255 mask in a specified array (an img_u8 for instance).
I have also regenerated the build files using ant 1.8.2 on Linux, but added them as a separate commit because you might want to regenerate them by yourself (otherwise you can squash the two commits). 

Cheers