Added possibility in the class DetectionBasedTracker to work as a tracker only -- without the mainDetector. 
In this case new objects will be added into it by the method addObject(const cv::Rect& location).

revision 8721 vas merged to head. Detection based tracker interface changed. cpp and android samples updated.

Warning: changes beak binary compatibility

Two colormaps removed from the list of colormaps, as they are no visually improved enhancement to a Jet colormap.

Documentation for FaceRecognizer started (not added to toc of contrib/doc/contrib.rst yet). CSV file for the samples/cpp/facerec_demo.cpp added. Added some more exceptions to warn the user, when passing bad aligned data.

Exceptions now go into CV_Error. Added thresholding to the FaceRecognizer and updated the demo accordingly.

Several exceptions added to the available FaceRecognizer classes and helper methods, so wrong input data is reported to the user. facerec_demo.cpp updated to latest cv::Algorithm changes and commented.

Merged lda fix from 2.4 branch (Fixed reconstruction, so that the mean is correctly added to the reconstructed image.)

Added a check of the DetectionBasedTracker's inner state in the main thread function of this class. 
This change should fix a multithread bug in the class.

FaceRecognizer class is now derived from Algorithm, therefore it's possible to set and retrieve the parameters using conventional Algorithm::set and Algorithm::get methods