This is ECJ's PBIL package.  To see this package in action, try running ECJ
on the file "ec/app/sum/pbil.params"

PBIL has a custom breeder and no breeding pipelines.  However, most of the work 
for PBIL takes place inside PBILSpecies.java, and the breeder is little more 
than a wrapper to call methods there.  So we have:

PBILSpecies.java		PBIL's species object.  PBIL uses
				IntegerVectorIndividuals for its representation.
PBILBreeder.java		Custom breeder for PBIL, largely calls
				code in PBILSpecies


