Fix for the initialisation of untemplated object. (#42)

Untemplated objects can be managed through the Toolbox library, but
their construction when referenced would error because the `template`
argument wasn't passed. It is now passed as None.

riscos_toolbox/base.py

@@ -89,7 +89,7 @@ def parent(self):
         if id in _objects:
             obj = _objects[id]
         else:
-            obj = Object(id)
+            obj = Object(id, None)
         if comp_id == 0xffffffff:
             comp = None
         else: