refactor enter preparing
Merge pull request #64 from fengjingchao/dev

refactor enter preparing
fix travis: glog
Merge pull request #65 from fengjingchao/dev

fix travis: glog
add network layer
Merge pull request #66 from fengjingchao/dev

add network layer
finish network transporter
Merge pull request #67 from fengjingchao/master

finish network transporter
Merge pull request #69 from go-distributed/master

Master