Help output

[danryan]

For example, hal help should print out all handlers that have help or usage information. At present there is no way for a user to know exactly what their bot will respond to without looking at the code.

[tcolgate]

This would be really good, and could make use of the description and usage info (not quite sure how they are exposed otherwise).

[onbjerg]

Tried to implement this myself using a handler, but was unable to. Any progress?