MVC slides

Going to create this as a PR and then merge it, just so I can make some notes and people know it's up.

Here's the slides as presented, but with the mismatched code that I didn't catch corrected. I also fixed one of the association images that had a different foreign key.

These really aren't great for reading on the web because I tried to avoid reading-the-bullet-points syndrome by doing a lot of slides with a single line or image. I will circle back around and add some "speaker note" type text to the bottom of these kind of slides to explain their purpose. (Some are just jokes.)

This was my first go at presenting, and I'm not very good, so after that, don't consider it permanent. Maybe some parts can be recycled, move the motivation for resources-as-abstraction to HTTP, slim down the rest?