Bit of cleanup and reorganization.

Changes to be committed:
renamed: debinningMath/dataGen.py -> debinningCore/dataGen.py
renamed: debinningMath/plotting.py -> debinningCore/histPlotting.py
modified: examples/debinningDemo.py
modified: examples/discriminationMC.py
modified: examples/nfrDemo.py
modified: examples/nfrVrHDemo.py
renamed: debinningCore/vsHistogram.py -> examples/vsHistogram.py
modified: examples/vsMeerkat.py
modified: examples/zeroVarianceLimit.py