Add GPO ops-monitoring support.
The pieces are: * A monitoring daemon (clientside/protogeni/shared-node-monitor), which runs in each Xen shared node dom0, and gathers node and interface statistics. It communicates these over the event system with... * A listening daemon (event/monitoring/shared-node-listener), running on the local boss node, and inserts everything it hears into the MySQL database "monitoring". This database is also used by... * A site-wide monitoring daemon (protogeni/scripts/mondbd), periodically polling the normal testbed database (nodes and interfaces tables) and copying snapshots of the important pieces into the monitoring database. * The monitoring database is also read by a WWW front end invoked as a WSGI process by Apache. This front end is developed by the GPO and modified to work with ProtoGENI, and is maintained in an independent repository.