Exporting patch masks does not automatically make a PatchStack, which forces them to all be the same size

By default, return non-expanded patches and masks; allow contour and mask overlays in non-expanded patches

Standardize patch (mask) getters return ad-hoc DataFrames, and _acc methods wrap these in PatchStack accessors (which automatically become shape of largest patch)

Removed solidity from features, this was no longer being used and was triggering convex hull warnings

Implementing alternative dataframe generation where z-positions are in object map, i.e. do not need to be de-projected from raw

Implemented and tested object identity labeling in 3D with and without connectivity between z-frames

record entry returned by object class map export is no longer a dictionary of paths, but rather one path for object map

Now that RoiSet is in base, remove dependency on ilastik in its test; tests now open segmentation mask from file

Progress on testing classify_by method; need to pass preference of channel to patch generator without disrupting existing options to export RGB / multichannel stacks