Merge pull request #12 from Semihalf/dev-vnswif-listener-freebsd

agent: Interface/Address/Route change in system observers
agent: Processing agent side originted messages with route change

VnswInterfaceListener is now able to react to events requiring it
to alter route, originating from the agent side.
agent: Processing agent side originted messages with route change

VnswInterfaceListener is now able to react to events requiring it
to alter route, originating from the agent side.

Post-review changes.