Issues:
- The `change` event was not dispatched in MaskEditor.svelte when an
undo/redo was performed. Therefore, if the user then closed the editor
or switched to another note without performing an operation that would
cause the `change` event to be dispatched, the undone or redone changes
were not saved to DB.
- When `IOMode.kind === "edit"` (i.e., Edit Current or Browse), the
beginning of the undo history was a blank canvas, not a canvas with
existing masks. Therefore, if you continued to undo to the beginning of
the history, the masks that existed when you opened the editor would be
lost, and they would not be restored even when you performed a redo.
- In the 'Add' dialog, the undo history was not reset when starting to
create a new IO note after adding an IO note.
Also add a small UI improvement:
The undo/redo buttons are now disabled when there is no action to
undo/redo.
* setup mask editor in note editor
- add image on mask button click (only one time)
- show hide add button for io on notetype change
- hide field in io notetype
- icon for toggle
and replace image
* add update io notes
* Tidy up i/o notetype check and fix error
- Make it a method on editor
- Use .get(), because the setting doesn't exist on older notetypes
- Pass the bool value into the ts code, instead of the enum
* reset io page after adding
* remove adjust function & add target for mask editor
* handle browse mode & merged sidetoolbar and toptoolbar to toolbar
* fix: shape, button click in browse, dropdown menu
* add arrow to add button
* store for handling visiblity of maskeditor
- remove update button in edit mode, implement autoupdate
* update var name
* simplify store
