polygon-edit: highlight prefs with polygon in pref list
polygon-edit: now we can remove deserialized polygon
polygon-edit: show all polygons
polygon-edit: show all dots
polygon-edit: now we can drag & select a dot of non selected polygon
polygon-edit: click existing dot to add it on "add mode"
polygon-edit: unselecting dot
polygon-edit: create inner line by alt + drag
polygon-edit: support for deleting inner line