Router events (WIP Attempt 2)

[wesleytodd]

See #49 for previous discussion.

I made a few other notable changes:

• The events are now given both the request and response. I thought this would be useful if someone wanted to use the response status code in their logging or stats.
• I added the bubbling that was talked about, but obviously only for the two events now implemented

NOTE: if we decide to move forward with this PR then I can clean up the git history.