Congrats print all

* Added an API to check for progress on Frozen (printing not displayed if user hasn't done any Frozen levels)
* Print HTML is ajax'd in.
* Printing is hidden if user is directed to /congrats from a different tutorial (with JavaScript)
![congrats-print](https://cloud.githubusercontent.com/assets/1592484/5307835/dca9db12-7bc5-11e4-9cd9-c97535b8d1f3.PNG)

long line.. move comment above?
(btw, you can always use our localhost.staging.code.org technique.)