BUG: Adding missing additional docs as data_file in python setup

Change-Id: I3fe29285a563bf72669bef2cca2b43c37dc18856
Adding Threshold measurement results for histogram based filters

Change-Id: Ib57888bce67a5e93ba4f2ffd90b17b4ffde83384
Merge topic 'SIMPLEITK-505_AddThreadholdMeasurement'

e4a385af Adding Threshold measurement results for histogram based filters
Merge topic 'SIMPLEITK-500_AddAdditionalDocsToPythonPackages'

e0a8cb35 BUG: Adding missing additional docs as data_file in python setup