Added ignore_group_order and --ignore_group_order argument to flip and combine groups when using groupby, i.e. combining e.g. group1-group2 and group2-group1

Changed how flipping and group reassignment is implemented

Fixed zooming near diagonal

divide_pups now allows dividing even if columns are different, gives warning instead

Added additional tests

Bug fixes and logs/warnings added

Changes to walkthroughs