in-app product management in developer pages (bug 956334)

https://bugzilla.mozilla.org/show_bug.cgi?id=956334

Definitely needs some UX but this is on hold now.

![in-app-products](https://cloud.githubusercontent.com/assets/211578/2555805/521b0892-b6c5-11e3-8ba1-cffe2a3bacd6.gif)