Refactored and cleaned up the idmapper directory; it's been so changed by evennia that it makes little sense to keep the original structure (which was intended for adding an app into). Resolved the unittest errors with the idmapper.

evennia/commands/default/system.py

@@ -666,7 +666,7 @@ class CmdServerLoad(MuxCommand):
         if not _resource:
             import resource as _resource
         if not _idmapper:
-            from evennia.utils.idmapper import base as _idmapper
+            from evennia.utils.idmapper import models as _idmapper
 
         import resource
         loadavg = os.getloadavg()