Made prettier a bit more modular, as promised.

(#9)
Beeminder bit doesn't work any more (which is kind of crucial), but this may be a change on their end rather than ours.
Merge commit 'd24fae41ff71c4af0c8a89d777aa14c99fa10a10' into prettify
Merge pull request #13 from j-po/prettify

Prettify