ENH: added 80th & 95th percentiles
ENH: added features for 80th & 95th percentile calculation
ENH: added ExtractRepositoryInfo for versioning provenance
Added CMake script to track the git hash for the version of the software used
to generate the output.
ENH: changed so CLI outputs the software revision
Updated CMakeLists so vtkQuantitativeIndicesExtVersionConfigure.h can be found by the CLI
ENH: read the software revision from the output of the CLI
An instance of the widget must be created and the CLI must be run in order to retrieve the software revision.
If both criteria are met, the revision may be retrieved using Python command slicer.modules.QuantitativeIndicesToolWidget.software_version.
ENH: output variance instead of standard deviation

Quantitative Indices module uses variance.  Filter updated for consistency.
ENH: updated method for retrieving variance.

GetStandardDeviation() changed to GetVariance()
ENH: remove higher percentile calculations for now