Raise exception if send request in non-broadcasting phase.
Fix the bug of SimpleLog found in jepsen test.
Optimization on FastLeaderElection.

1. Everybody broadcasts its own vote at beginning.
2. Don't clear message queue when participants go back to recovery case
since it might remove election messages.
Move the handling of query leader message after heartbeat check.

Found it by running jepsen test.
Fix the timeout bug in jepsen test.
Merge pull request #172 from EasonLiao/raise_exception

Don't buffer the request in non-broadcasting phase.
Bump version to 0.2.0-SNAPSHOT.
Fix publish-artifacts.sh.

- Run the script with -e option so that the build fails if the script
  fails.
- Push javadoc for all the branches.
- Update git repo url.
Merge pull request #175 from m1ch1/master

Fix publish-artifacts.sh.
travis: update github token.
publish-artifacts.sh: update repository name.
publish-artifacts.sh: fix a typo.
publish-artifacts.sh: ignore git rm errors.
Update README.md
Add a documentation directory.
publish-artifacts.sh: fix doc directory name.
Optimizations on FastLeaderElection.

Do not discard PROPOSED_EPOCH message during election.
Fix netty transport.

1. The server who clears the transport shouldn't get the DISCONNECT message.
2. Fix the null pointer exception.
Limit the size of the pending requests.
Merge pull request #176 from EasonLiao/fix_0.2.0

Fix for 0.2.0