Simplify printing procedures

Use opencv's print() procedure in place of my own procedures to output
matrices and std::vectors.

Interestingly enough, operator<< does not work for matrices, when called
from my .cpp files in src/ subfolder of the optim module, although it
works when called from tests and stand-alone programs, compiled with
opencv. I think, this requires investigation and, maybe, bug report.

modules/optim/include/opencv2/optim.hpp

@@ -44,7 +44,6 @@
 #define __OPENCV_OPTIM_HPP__
 
 #include "opencv2/core.hpp"
-#include <iostream>
 
 namespace cv{namespace optim
 {