Remember button grayed out when no changes made

[Iznik285]

Windows 10 / MF 1.52.0

As a new feature suggestion, would it be possible for the Remember button to be grayed out when entering a note or notebook. Then enable it when changes have been made to the notebook or note.? It would be a useful indicator.

[omgtehlion]

I tried to fix this in https://github.com/dvorka/mindforger/commit/1ab6ef250e8a7236b443b082730f3ec3d7795e7f

I might have placed code not in the correct class, though...

This change also allows further improvements, like not asking when pressing [Esc] on unchanged notes