Tracking-Learning-Detection and MedianFlow

This contribution includes the following logical components into
tracking module:

*) Change Rect to Rect2d into headers for Tracker's methods;
This contribution includes the following logical components into
tracking module:

*) Change Rect to Rect2d into headers for Tracker's methods;
*) MedianFlow tracker;
*) extensible benchmark to compare trackers interactively and
assess
them quantitatively;
*) TLD tracker (work-in-progress);

Work was funded by Google Summer of Code 2014 initiative. Mentors:
Gary
Bradski and Vadim Pisarevsky.
classes should not have any private methods, constructors or data members. They should be just interfaces, for which you provide implementations in cpp files. Please, see opencv/modules/video, background subtraction classes on how to do that