logging

[Jim Donofrio]

Since we only use logging for the most part to print out basic 
information for comparing expected inputs and outputs, what are the 
thoughts on switching to the jdk logger. I admit to not knowing much 
about logging but there seems to be tons of complaints out there about 
commons-logging which we dont really need since our logging needs are 
simple. We could also remove our dependencies on log4j and 
commons-logging even though hadoop brings these in transitively anyway.

slf4j would be another option but then users would have to no to include 
a slf4j binding, I would rather avoid that.

If you seem to agree, I will make this change.