Fix other minor issues in DIALOG_PLOT_SCHEMATIC.
Previously the export was always in inch (and in mm in Pcbnew)
kicad-cli always export in mm (like in Pcbnew)
Recommendation is to avoid using the year nomenclature as this
information is already encoded in the git repo. Avoids needing to
repeatly update.
Also updates AUTHORS.txt from current repo with contributor names
Includes:
- Fix GAL to draw closed polygons in eeschema
- Add functionality to eeschema to draw arbitary polygons
- Update polygon item previews to have customisable edge colour
- Add new SCH_RULE_AREA class, derived from a poly SCH_SHAPE
- Add SCH_RULE_AREA to paint and plot methods
- Add new rule area color preference to themes
SCH_EDIT_FRAME::SetCurrentSheet( xxx ) was used to switch to a sheet, but
SCH_EDIT_FRAME::SetCurrentSheet() has side effects to the current VIEW
(clear some data used to show the sheet on screen) and does not fully
restore the "old" screen
SCHEMATIC::SetCurrentSheet( xxx ) is now used to switch to a sheet
