Send/Receive raw message API request - NetIDE

The NetIDE project requests new API methods to aid in its interoperability service for other opensource controllers. See attached PPT for presentation.

RPC methods:

• GetOFVersion() -> Required to support handshake with legacy controllers.
• SendOFMessage() -> eg, PacketOut, FeaturesRequest, etc

Notification:

• Message Received (OF object) -> eg, PacketIn, FeaturesReply

Feedback from the OFP call on 2/May:

• other projects are also requesting a GetOFversion() method or similar for a given switch. Therefore, a better implementation may be to publish this property to the inventory datastore.
• OFP team would prefer if the implementation for this API was in a separate Karaf Feature not installed by default, eg, odl-openflowplugin-netide-service (or similar)
• An initial patch (not to be merged) will be pushed for review/comments