Merged requested to merge kmorel/vtk-m:field-selection-as-member into master
Previously you passed a FieldSelection to Filter::Execute to specify which fields to pass from input to output. There is no real reason for this as other information about input and output fields are member variables to Filter. This moves field selection as a member variable as well. (This should also help confusion when updating old code to new to prevent users from mistaking field passing with input fields.