Agent - Add Support for Receiving Unassigned OPCODEs

*Agent parses message with OPCODEs 6 and 7 and calls
for a create and delete event, respectively.
*There isn't much done at the moment, but they will call into
the pluggable backend when implemented.

Change-Id: I48c2deb729c853bebec74a04b6c97c89426000c1
Agent - Add Backend Capabilities

*Create a Base Backend
*Call into it on NOTIFY, CREATE, DELETE events
*Port a Bind9 Backend

Change-Id: I730e666bbd9db48d1f6793f8f6b48decaee39cb9