Rebranding CISimple => Ship.io

Hi, I work for Electric Cloud, which recently purchased CISimple. We have been rebranding the service as Ship.io, and I updated your notifier app accordingly. I also generated a new screenshot (incorporated in our Dev Center) and put a copy in your app, and updated README.md to get the screen capture from there. That way, if we move assets around in our app, you won't be affected.

My apologies that this PR is so big. I renamed everything *and* modified cisimple references. I've also noticed that the app reports a build is queued when it starts running. I'm not sure if that's an issue on our end (not publishing the queued event to pusher) or on yours.

I also fixed your unit tests (in that they weren't compiling), but I couldn't run them.