Autoupdate on changes and pushes

Bot will now exit with code 42 when going for an update
./run.sh was updated to actually trigger an update.
It will also restart the bot in the event of a crash.

- added an `update` private command
- added a `crash` command for testing purposes

GitHub bot messages can trigger an update, so we can use them as
a hook.

Also, the bot now keeps unhandled exception in log/error.log