Fix hardcoding of connection info to remote datacenters

peer datacenters and their corresponding controller
public ips and gateway puclic ips are stored in inception.conf.
Merge pull request #50 from powerist/working

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

Improve code modularity
Differentiate priorities

Packets are matched on the order of datacenter prefix,
local addresses, and switch prefix.
Merge pull request #52 from powerist/working

Differentiate priorities
Flow redirection after live migration

1. Change gateway flows in all datacenters to new vmac
2. Send gratuitous ARPs to all guests which have requested
Merge pull request #53 from powerist/working

Flow redirection after live migration
Fault-tolerant live migration

The live migration, including RPC, is logged each time.
The back-up controller checks the logging and finish all
remaining tasks.
Property: Live migration eventually finishes consistently.
Merge pull request #54 from powerist/working

Fault-tolerant live migration
Fault-tolerant source learning and ARP learning
Merge pull request #55 from powerist/working

Fault-tolerant source learning and ARP learning