[JAVA] Add agent interface + other stuff

Other stuff:
- Add return error code to system
- Add debug cli option
- Add some javadocs
- Set default stepPrint to zero
- RNGTypeConverter uses Enum's valueOf to detect rng
[JAVA] Use latch instead of semaphore + fix stepPrint

Other stuff:
- Add more javadocs
- printStackTraces only in debug mode
- Sim. threads return on exception
[Java] Complete javadoc + More efficient seed gen for single thread
Merge branch 'java'

Conflicts:
	java/src/org/laseeb/pphpc/PredPrey.java