Container Tab

Adds a container tab to the inspector.

- [x] Add container tab that lists all cached types and singletons
- [ ] Add search
- [ ] Add tests
- [ ] Icon for container nav link

![screen shot 2014-10-11 at 10 38 46 pm](https://cloud.githubusercontent.com/assets/1061742/4603911/f20923c6-517e-11e4-9460-f3f193ff6fc8.png)