Add functions PyUnicode_Append() and PyUnicode_AppendAndDel() that mirror
PyString_Concat() and PyString_ConcatAndDel() (the name PyUnicode_Concat()
was already taken).

Change PyObject_Repr() to always return a unicode object.

Update all repr implementations to return unicode objects.

Add a function PyObject_ReprStr8() that calls PyObject_Repr() and converts
the result to an 8bit string.

Use PyObject_ReprStr8() where using PyObject_Repr() can't be done
straightforward.
diff --git a/Objects/moduleobject.c b/Objects/moduleobject.c
index f188515..daf24eb 100644
--- a/Objects/moduleobject.c
+++ b/Objects/moduleobject.c
@@ -198,9 +198,9 @@
 	filename = PyModule_GetFilename((PyObject *)m);
 	if (filename == NULL) {
 		PyErr_Clear();
-		return PyString_FromFormat("<module '%s' (built-in)>", name);
+		return PyUnicode_FromFormat("<module '%s' (built-in)>", name);
 	}
-	return PyString_FromFormat("<module '%s' from '%s'>", name, filename);
+	return PyUnicode_FromFormat("<module '%s' from '%s'>", name, filename);
 }
 
 /* We only need a traverse function, no clear function: If the module