Edited graph theory notes

By request, this page contains a slightly edited version of last year's notes, that removes the material we didn't cover (longest paths and applications to scheduling, surfaces beyond the torus, the A* algorithm), and adds the few extra things we did this year that weren't covered before (Prim's algorithm and gluing formulas for the chromatic polynomial; that's it). It's basically last years notes with the unimportant bits chucked out, grouped into sections like the online notes, with a few little bits added, and was done quickly; I would still probably recommend using last year's notes and the incomplete this year's notes together in tandem, but if you insist on it all in one place, here it is. The sections are linked to in the tabs above, or: