improve `editTopo.py`

[aekiss]

Laundry list of things to consider doing one day...

• remove toolbar? but keep status bar.
• only edit if in pointer mode - use .get_active() https://matplotlib.org/3.1.0/api/widgets_api.html
• switch to pointer after zoom/pan https://matplotlib.org/3.1.1/api/backend_tools_api.html and https://matplotlib.org/3.1.1/gallery/user_interfaces/toolmanager_sgskip.html and https://matplotlib.org/3.1.1/api/backend_managers_api.html#matplotlib.backend_managers.ToolManager
• allow multiple points to be changed by dragging - draw_event https://matplotlib.org/3.1.1/users/event_handling.html
• save .nc with save button
• show edit info when clicking on point https://mplcursors.readthedocs.io/en/stable/
• integrity checks - maybe with https://github.com/mom-ocean/MOM5/blob/master/src/tools/make_topog/topog.c ? https://github.com/mom-ocean/MOM5/blob/master/src/tools/make_topog/topog.c#L858

[micaeljtoliveira]

@aekiss Shall we move this issue to the domain-tools repo?

[aekiss]

yep, good idea