metomi/rose#351: migrate menu and add latent page support
metomi/rose#351: reshuffle methods into new classes
metomi/rose#351: new modules
metomi/rose#351: split up loader.py
metomi/rose#351: rename remnants of loader.py
metomi/rose#351: rename panel.py
metomi/rose#351: handle reload
metomi/rose#351: fix
metomi/rose#351: split stack.py into ops package
metomi/rose#351: tidy up stack.py split
metomi/rose#351: split main.py
metomi/rose#351: bugfixes for rearrangement
metomi/rose#351: undo working for variable modify