Add possibility to see model fetch requests

Current state of affairs:
- It's possible to see fetch request in the right table

To be done:
- detailed info about request (string representation of the predicate). I'm planning to call detailed info of request by right click as for entities, is that Ok?

![513a70b1e4b042563c9ff86b](https://f.cloud.github.com/assets/829783/238763/017950dc-8846-11e2-82ff-e24d62a30984.png)