bug fixes on seq update.
bug fix on Union and test on fast path
fix panic cases
fix preaccept-ok/-reply
add notAbleToFastPath
Merge pull request #33 from fengjingchao/inst

bug fixes on seq update.
nilStatusProcess testing covered, fixed some small bugs
change freshlyCreated to isAtInitialRound
Update README.md
Merge pull request #34 from yifan-gu/dev

nilStatusProcess testing covered, fixed some small bugs
cover the preparingProcess
Merge pull request #35 from yifan-gu/dev

cover the preparingProcess