move bm tests into bm dir, run them after unit test finished; supports specifying custom data handler
JRuby version supports multithreading mode:
1. new SamplingProf with multithreading=true and a block to process data
2. start / stop to add / remove current thread from the sampling thread
3. all threads sampling together, flush out by a period time defined by flush count which is third argument of the initializer method
4. added terminate method to kill the sampling thread for multithreading mode, should behavior same with stop in single thread mode

Move Sampling to a standalone java file
bump up version