HTML5 Doctype, Larger iframes, and Documentation

There's a lot of files that are changed, but most are small changes.

1) Vast majority of file changes are to move to HTML5 doctypes. 
2) I made a couple changes to the way iframes are handled so that they are now in a div. The upside is that their height now scales with the window height. (Course sharing videos still need work.)
3) README now has some WIP documentation, but it's a start!
I gave it a structure we can hopefully expand. It also includes basic license info, which we should probably clarify a bit more as well.
4) There's terrible diff cruft in bjc-loader due to whitespace changes for some reason... I can go back and fix it if necessary.
5) The links in the Berkeley_BJC course page are now more relative. I'm hoping to continually make more and more links relative instead of using /bjc-r

I think this is ready to merge, but I'd like someone else to give it a look over, just to be sure!