OFNetwork resource with a capability for flow provisioning.

OFNetwork resource represents an OpenFlow domain.
OFProvisioningNetworkCapability has methods to allocate, deallocate and replace flows in the domain.
It is also able to retrieve allocated flows, although current implementation is not in sync with underlying resources.

Implementation provided by internal driver delegates the allocation of each individual flow to IOpenflowForwardingCapability.
Refactor OFERTIE NCL to use OFNetwork, instead of SDNNetwork.
Fix ofertie.ncl unitary tests.
Network Monitoring capability skeleton.
Merge branch 'develop' of https://github.com/dana-i2cat/opennaas into feature/sdnnet-monitoring-capab
NetworkStatistics class refactored and @Get annotation in method.
Merge branch 'feature/sdnnet-monitoring-capab' of github.com:adrian-rosello/opennaas into feature/sdnnet-monitoring-capab
Features for ofnetwork
Add method in NCLProvisioner API to retrieve relation between circuit and its flows.
Merge pull request #758 from adrian-rosello/feature/sdnnet-monitoring-capab

SDN-monitoring skeleton
Test for NCLProvisioner

The test has been updated to use ofnetwork instead of sdnnetwork.
SDNNetworkFlow is no loger used and a List of NetOFFlow has taken its place.
Fix model update in AllocateFlowAction.

Check the list exists before trying to add an element (avoiding NullPointerException),
and create the list with only that element, in case it did not exist.
Fix GetAllocatedFlowsAction return value.

GetAllocatedFlowsAction now returns a Set<NetOFFlow>.
GetNetworkStatistics capability method.
Avoid java.lang.UnsupportedOperationException when updating model in DeallocateFlowAction.

Avoid java.lang.UnsupportedOperationException when removing element from a list that does not accept the remove operation.
Applied solution is to provide an implementation for List that do supports remove operation.
Fix error in test
Increate NCLProvisionerTest to check removed flows are no longer in switches.
GetNetworkStatistics action.
Convert SDNNetworkOSGIIntegrationTest into OFNetworkOSGIIntegrationTest.

New test uses ofnetwork and NetOFFlow.
Remove sdnetwork and associated features. sdnnetwork has been replaced by ofnetwork.