uhm.. wouldn't it know anyways? I mean, it would have done `this.driver.on('error', function(err){ this.status.sendError('Problem with playlist driver: ' + err.message) })` or whatever handling it wants to do.

The error is not just a string, it's an object (well, right now it's the message plus the stack print, but this might change if javascript got smarter). If the handler wants to print it or send it to caspa, I think it should (could) prepend where it comes from itself. In any case, I don't think we should be parsing string to figure out where an error is coming from.

I could make a specific Error constructor, something like `MongoPlaylistDriverError`