Modifying DevStack to support FlowVisor 1.0
Added Janus host and port info in controller and agent node localrc's
gen-local should ask user if Janus is enabled when generating agent nodes
Added further support for Janus in stack.sh script
  - Use Ryu 'ryu2janus' branch if Janus is enabled
    - Until Quantum has its own drivers for Janus, need to maintain 2 branches for Ryu
  - Pass Janus host and port info to Ryu OF event forwarding app
Migrate Janus DB from 'ryu' to 'janus'
Set default ports for Janus: 8095 for admin APIs and 8100 for public APIs
  - Avoids confusion (Ryu uses 8090 when Janus is not enabled)