Add a few CIS courses from UPenn

Namely, I'm adding CIS 581 (computer vision) and CIS 500 (software foundations) to the list.

There was a complaint on the [HN thread](https://news.ycombinator.com/item?id=8806910) that this page didn't have enough theoretical CS courses listed, so I decided to start one with CIS 500. It doesn't really belong in the Algorithms section, and, in my opinion, doesn't really fit nicely with the rest of the courses under Misc.