Added the "Mask operations on matrices" tutorial (with its sample). Plus modified some other core tutorials.

Added Fernandos first tutorial regarding SVMs. Extended the global links (conf.py). Corrected the author names. Minor modification to the dft tutorial. 

fixed and improving formatting in opencv2refman.pdf. added support for n-channel mask in Mat::copyTo() and n-channel images in cv::compare(). fixed 2 compile warnings in opencv_python.