Tvl1 chambolle

I adapted the TVL1 optical flow computation method to accomodate illumination variation according to the method described by Chambolle and Pock in http://link.springer.com/article/10.1007/s10851-010-0251-1

The performance loss is 2% when setting the new parameter to 0, and 30% when actually using the feature. It is not used by default.