Added default grey image in PyDIP `MeasurementTool.Measure` function. Fixes root cause of #6.
Added default grey image in PyDIP `MeasurementTool.Measure` function. Fixes root cause of #6.

DIPlib/diplib,DIPlib/diplib,DIPlib/diplib,DIPlib/diplib,DIPlib/diplib,DIPlib/diplib