When searching templates, check also `default` theme directory.

diff --git a/loader.py b/loader.py
index b59414b..98ad53f 100644
--- a/loader.py
+++ b/loader.py
@@ -6,9 +6,12 @@ def load_template_source(template_name,dirs=None):
   theme = getattr(settings,'THEME','default')
   base = settings.TEMPLATE_DIRS[0]
   path_theme = join(base,'themes',theme,template_name)
+  path_default = join(base,'themes','default',template_name)
   path_base = join(base,'base',template_name)
   if exists(path_theme):
     path = path_theme
+  elif exists(path_default):
+    path = path_default
   elif exists(path_base):
     path = path_base
   else: