Histogram Backprojection

This is an implementation of Histogram Backprojection based on:
Swain, Michael J., and Dana H. Ballard. "Indexing via color histograms." Active Perception and Robot Vision. Springer Berlin Heidelberg, 1992. 261-273.

(This was submitted one year ago, reviewed and certified OK, but somehow I corrupted my git repo, so merging was not possible back then. So I am resending the same)


![figure_1](https://cloud.githubusercontent.com/assets/678900/2663751/29a61fc6-c063-11e3-93da-94ed3f405e3d.jpg)