Add match processor

[yuripourre]

The goal of this algorithm is to find an imageSource inside another imageSource.

Mask may contain alpha pixels to be ignored (a = 255);

Return x,y position

int[] MatchProcessor.process(ImageSource mask);

int array is more general than specific Objects.

step can useful to skip pixels. Is easy to skip mask or image but is hard to do with both.
stepX requires you to check (0,0) and (1,0)
stepY requires you to check (0,0) and (0,1)

Maybe useful algorithm:
https://stackoverflow.com/a/297820

[yuripourre]

One idea is to check diagonal instead, but I am not sure if it would for every case.