title: How to convert C++ array to opencv Mat
body: <p>What is the fastest way to convert a C++ array into an 2D opencv Mat object?
  Brute force method would be to loop over all entries of the 2D mat and fill them with values of the array.<br>
  Is there a better / faster way to do that?
  Could I somehow just give pointer of the array to the 2D matrix?<br>
  (I'm using opencv 2.4.8)</p>