Merge pull request #36 from fengjingchao/inst

fix test
Merge pull request #37 from fengjingchao/inst

finish replication test
Merge pull request #38 from fengjingchao/inst

add checkpoint cycle
style(replica.go, dummyTR.go)
Merge pull request #40 from yifan-gu/dev

style(replica.go, dummyTR.go)
finish tarjan scc
test(instance_test.go) add test for handlePropose and handlePreAccept
Merge pull request #42 from yifan-gu/unitest

More testing on instance state machine
Merge branch 'master' of github.com:go-distributed/epaxos into inst

Conflicts:
	replica/replica.go