Clusters dashboard

Totally work in progress, but at least applies now (after lying dormant for 3 months). Not sure if it even works, to be confirmed... I also need to do a massive rebase to make sure it looks like I know what I'm doing. Use at your own risk.


Urgh.  The correct way of doing this would be to allow other barclamps to provide their own chunks to the dashboard via mini-plugins.  Then the `nova` barclamp would take care of displaying compute nodes on the dashboard.  Sounds tricky though; I wonder if it could be done without too much effort?