Log the beginning and the end of each unit test method.

This patch adds a base class TestBase for all the test classes to
inherit from. The base class defines a junit test watcher to log
the beginning and the end of each test method to make it easy to
associate log messages with the test method that generated them.
Merge pull request #32 from m1ch1/unittest

Log the beginning and the end of each unit test method
Merge pull request #31 from EasonLiao/master

Make Fixbug works
Single Node Zab implementation.