added a modified version of erics memleak script for guis

svn path=/trunk/matplotlib/; revision=3133

Author: jdh2358

unit/memleak_gui.py

@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 '''
 This illustrates a leak that occurs with any interactive backend.
+
+Run with : python memleak_gui.py -dGTKAgg   # or TkAgg, etc..
 '''
 import os, sys, time
 import gc