PyNutil only worked for method = "all". Fix so that it works for "per_pixel" and "per_object".

The reports now give same region pixels as Nutil

fixed issue where PyNutil would fail on sections that have 0 pixels, or where min object size was set too high

Slice reports and whole series reports now correct

There is an error in the combined_report (it sums the area_fraction).

per_section_meshview
per_section_reports
sections_combined_meshview
sections_combined_report

Working session with Harry.
Read in flat files from a folder. Scale flat files to size of seg. Calculate region areas per slice. Create slice reports with region areas and object areas. Create report for all slices by summing slice reports. In progress.