Routing nfv

The API of the OpenflowForwarding Capability contained two methods exported in same path, but with different parameters. They have been unified and the method receives OFFlow as parameter.

Solved NullPointer in CreateOFForwardingAction of OpendatyLight module if the EtherType was null.
This unification works, but de ObjectMapper will ignore extra parameters taht are contained in `OpenDaylightOFFlow` and `FloodlightOFFlow` and other subclasses of `OFFlow`. It seems that in current use cases there is no problem, but with Ryu there could some issues.