Differentiates better between the EDA_ITEM IsModified(), referring to
items themselves changing and the EDA_SCREEN IsContentModified(),
referring to whether we have made any unsaved changes.
Some differences are due to difference between libraries being files
in symbol editor and directories in footprint editor, but this unifies
most of the rest.
It also dispenses with the save-to-library vs save-to-document distinction
in the GUI because it makes for too much variability in the GUI, was
implemented differently between the two editors, and isn't needed as much
anymore now that we have the highly visible infobar.
There was also an issue that the save-to-board icon occupies the same
location and has the same size/shape/colours as the Board Setup icon in
PCBNew.
Fixes https://gitlab.com/kicad/code/kicad/issues/7215
One way to do this would have been to keep the Uuids in the editor
copy. However, this opens us up to errors if we forget a Save As or
export path and end up writing the Uuids out somewhere else.
In the end, it felt safer to store a map of the original Uuids and
restore them if we happen to save the editor footprint back to the
board.
Fixes https://gitlab.com/kicad/code/kicad/issues/7312
Jeff Young
Wayne Stambaugh
Marek Roszko
Ian McInerney
Seth Hillbrand
Jon Evans
Michael Kavanagh