Merge pull request #14 from rackerlabs/horizon_changes

Hide giturl modal window
On app manage screen, the image timestamps are now listed in
descending order.
Changed Memory Quota to Resource Flavor with OpenStack flavor types.
Also adds a "Rollback 1 Image Version" button.
Updates to Dashboard page

- Open App url link in a new tab
- Use Radio buttons to select an application, and present a single
Manage button.
- Refresh Dashboard page when a modal window is closed.
- Hide manage button when there are no apps.