Post deploy message

With the new `--track` option, it becomes a bit more important to indicate the success of a deploy after the stack monitor quits. This quickly adds that capability.

#### QA
- [x] Running a deploy with migrations on something using `--track` should yield something like this:
![](http://screenshots.chrisarcand.com/odeal.jpg)

- [x] Pressing `q` on the monitor at any time should quit normally without any message

- [ ] Should be a problem, but for a true regression case: Error messages on failed deploys should show as normal (don't know how to test that...)
I guess considering that's the only possible outcome at this point, and that a proper exit 0 _is_ success...