More logging

[ChrisCinelli]

Could you add more logging and use the great https://github.com/visionmedia/debug to do so?

In this way you can for example add here logging with debug('botkit:event:trigger')(event, ":", data);

When I had some problems, it has been difficult to find out what is going on and I had to add a few custom botkit.debug in botkit code. On the other end, some of these botkit.debug made the logs very noisy.

Using the debug module you can selectively enabling the kind of debug you want setting the environment variable DEBUG. It is a "standard" used by a lot on npm modules including express, socket.io, etc.

On a side note, it is unclear why botkit.debugalways log to the console and botkit.log it is more flexible and let you even choose to redefine a handler. I used to use Winston everywhere for logging but lately with docker and so many log collection services (ex: papertrail), I started sending everything to the console and capture that output. I would recommend that is a way or another you make log and debug work in the same way.