Merge pull request #44 from m1ch1/master

SimpleLog: fix javadoc formatting.
Refactor the Participant into a separate class.
Merge pull request #41 from EasonLiao/refactory

Refactory
introduce dummy log for testing.
Merge pull request #46 from EasonLiao/dummylog

Introduce dummy log for testing.
Update README.md

fixes #47.