Add basic contour functionality

This is the first round of stuff for contours to work. [#25]

Because vertices of contours must go in reverse to work correctly, I am putting them in an array, then firing them off backwards.  I have put in constants to account for the fact that the contours can be any kind of vertices, and I will put in the other two of those when I implement those two, but for the time being, I wanted to get this in and feedback it.