Maintain master and working copies of data structures, to enable saving single maps at a time

editor.cpp

@@ -9,14 +9,15 @@ Editor::Editor()
 
 void Editor::saveProject() {
     if (project) {
-        project->saveAllDataStructures();
         project->saveAllMaps();
+        project->saveAllDataStructures();
     }
 }
 
 void Editor::save() {
     if (project && map) {
         project->saveMap(map);
+        project->saveAllDataStructures();
     }
 }