Converted the constraints viewlet to a Y.View instance.
Fixed failing inspector constraints tests from viewlet to view changeover.
Merge pull request #165 from hatched/constraints-to-view

To QA
-----
Make sure you can change the values for the constraints in the ghost and service inspector. Also testing the databinding functionality using:

```var srv = app.db.services.item(0); var cst = srv.get('constraints'); cst['cpu-cores'] = '110'; srv.set('constraints', cst);```