title: Accessing a matrix element in the "Mat" object (not the CvMat object) in OpenCV C++
body: <p>How to access elements by row, col in OpenCV 2.0's new "Mat" class? The documentation is linked below, but I have not been able to make any sense of it. 
  <a href="http://opencv.willowgarage.com/documentation/cpp/basic_structures.html#mat" rel="noreferrer">http://opencv.willowgarage.com/documentation/cpp/basic_structures.html#mat</a></p>