YouTrack integration

https://github.com/bugsnag/bugsnag-notification-plugins/issues/62

All I have to say is - cookies are meant to be delicious…

![Screenshot](http://cl.ly/image/441x282T3f3h/Image%202014-07-15%20at%2010.45.53%20pm.png)
Ah, totally forgot about that, cheers @snmaynard!