do_Overlay -- a simple matlab script for image overlay

Matlab, for all of its (many, various, myriad) evils is unfortunately the language of choice in MR. Overlaying two black and white images in colour is often a bit of a PITA. This script aims to ameliorate the pain just a little.

I should point out that you still have to do the boring linear algebra of making sure that the orientations of the things you want to overlay are correct, however.