Bells and whistles et caetera

I couldn't start working on the interpreter without getting comfortable first... So I added a few things to the interface. Code editors driven by Codemirror, a proper syntax highlighter (which still doesn't catch a few edge cases), and even a fancy little scrollmap on the right-hand side of the screen, thanks to Pagemap.

I know I'll be tweaking this... like, forever. But now I can start setting up the interpreter!

Oh, and I added comments to the parser. Oldie goldies, /* ... */ and // ...