convert the polymer js web sample to paper

Convert the JS web app sample to use the paper elements. I tired to create a simple polymer / paper example that would give the users a good intro to polymer and paper without giving them too much code to delete. Also, fixed an issue w/ the web server discovered when I opened devtools on the sample paper web app (we returned a null content type).

@ussuri

![screen shot 2014-07-23 at 4 53 47 pm](https://cloud.githubusercontent.com/assets/1269969/3690521/87c5634e-1349-11e4-999e-d89383bb907d.png)
![screen shot 2014-07-23 at 9 22 48 pm](https://cloud.githubusercontent.com/assets/1269969/3690522/87c91bec-1349-11e4-965a-345e8938fcdf.png)