begin merging files which were previously in temp-squares directory into main

fcore/common-update.sml

@@ -0,0 +1,13 @@
+structure CommonUpdate =
+struct
+  (* unimplemented *)
+  fun getSaveSquaresMsg model = (model, [])
+
+  fun getLoadSquaresMsg model = (model, [])
+
+  fun getExportSquaresMsg model = (model, [])
+
+  fun useSquaresInNormalMode (model, squares) = (model, [])
+
+  fun squaresLoadError model = (model, [])
+end