Synnefo

Create quotas module

Create quotas module, containing functions for interacting with
the Quotaholder service.

Create QuotaHolderSerial table

Do not automatically update network state

Each modification in a BackendNetwork object, triggers an update
to the corresponding Network object. Until now this was done by
the BackendNetwork save() method. Now it is explicitly done
from the backend pross_network_status.

Add function for pretty printing tables

Extend Plankton API with shared-images

Extend Plankton API, to support listing all non-public images that
are available to the user. This can be done by issuing a GET to
shared-images/ and shared-images/detail.