implement opencv template matching

[robxu9]

In order to do that, we need to figure out how to get the image into a buffer that openCV can read -> so maybe png the files?

Then, via that buffer, have openCV process the image with matchTemplate.

for self reference:

• http://dasl.mem.drexel.edu/~noahKuntz/openCVTut6.html
• http://opencv-users.1802565.n2.nabble.com/Direct-from-buffer-to-IplImage-td5654441.html