Ryu actionset implementation for offwarding capability

Pull request introduces the Ryu actionset implementation.

First of all, the Capability model had to be refactored not to include Floodlight specific information. All classes containing FloodlightOFFlows were modified to include only OFFlow, which is the generic object for forwarding rules.

Second part of the implementation contain all the actions. Since Ryu does not classify flows with id, all actions contain a small part of logic handling model flows.