Merge pull request #50 from powerist/working

Fix hardcoding of gateway connection info to remote datacenters
Merge pull request #51 from powerist/working

Improve code modularity
Merge pull request #52 from powerist/working

Differentiate priorities
Merge pull request #53 from powerist/working

Flow redirection after live migration
Merge pull request #54 from powerist/working

Fault-tolerant live migration
Merge pull request #55 from powerist/working

Fault-tolerant source learning and ARP learning