Mega Refactoring + Feature Dump

[gingershaped]

Closes #43 and #9 (finally!)

To do:

• [x] Create the new chat machinery and parser
• [x] Move chat logic over
• [x] Move GH logic into its own file
• [x] Move chat bare-message commands into their own file
• [x] Fix up alternate command syntaxes

[gingershaped]

Note: I didn't actually test GitHub event reporting, so it's possible that's broken.