Mixed batch of minor bug fixes and cleanups.

src/commands/default/building.py

@@ -1018,6 +1018,8 @@ class CmdOpen(ObjManipCommand):
 
         else:
             # exit does not exist before. Create a new one.            
+            if not typeclass:
+                typeclass = settings.BASE_EXIT_TYPECLASS
             exit_obj = create.create_object(typeclass, key=exit_name,
                                             location=location,
                                             aliases=exit_aliases)

src/commands/default/cmdset_default.py

@@ -11,6 +11,7 @@ class DefaultCmdSet(CmdSet):
     Implements the default command set.
     """
     key = "DefaultMUX"
+    priority = 0
 
     def at_cmdset_creation(self):
         "Populates the cmdset"