Added an oilpaint filter for simplecv-js

I've been checking out some Image manipulation filters and I came across this filter which turns an image into an oilpainting of itself. I thought it would be fun to implement it in SimpleCV-js. But there are some limitations to the algorithm.

1) Since we compare a pixel with its neighbourhood of given radius. There are a large number of comparisons so the algorithm is a little slow.

2) For intensity levels  20 is a good number. you might want to use that.

3) keep the radius between 2 and 4 . if you increase it then the method will take a lot of time

4) since it takes time to execute you might want to wait a while than usual to see the result :)