Dynamic bus route/stop configuration using the robot brain

Instead of having to edit the environment variable and restart Hubot to get new stops/routes configured, just talk to him:

```
larcher: hubot add bus 10 n at stop 1180
hubot: Ok, added bus #10 Northbound at Stop 1180
```

Store all that config info in the brain.  Could still have an environment variable that would get loaded in if the brain was empty of bus data.
