ChangeTrackerPy - adding self test

https://github.com/fedorov/ChangeTrackerPy/compare/a850b00...42c14f1

RSNA2012Quant test in Slicer trunk should be updated to exclude ChangeTracker
part, as it is no longer built as part of the app
Merge pull request #278 from fedorov/update-ChangeTracker

ChangeTrackerPy - adding self test