Multi endpoint

merge #16 and #17 with amiconfig nova-ssh and occi

To test amiconfig cloud-stack wiht #16 and #|7

NEW: endpoint vmPolicy "static" -> slots driven, indicated by maxEndpointInstances, endpoint CS parameter
     endpoint vmPolicy "elastic" -> jobs driven, one by one

NEW: endpoint vmStopPolicy "never"
     endpoint vmStopPolicy "elastic" -> no more jobs + VM halting margin time
CHANGE: Both cases: VMs can be stoped from "Instances Overview" screen: VirtualMachineDB.py in function instanceIDHeartBeat:
Send empty dir just in case we want to send flags (such as stop vm)
TODO: The particular HEPiX method to ask VMs to shootdown from the IaaS site provider site (requirement to be specified by HEPiX)