fixed typo

git-svn-id: https://pycam.svn.sourceforge.net/svnroot/pycam/trunk@566 bbaffbd6-741e-11dd-a85d-61de82d9cad9

src/pycam/Geometry/Plane.py

@@ -43,7 +43,7 @@ class Plane(TransformableContainer):
         # a plane always consists of two points
         return 2
 
-    def reset_cache():
+    def reset_cache(self):
         # nothing to be done (but required for TransformableContainer)
         pass