Migrated demo code to not import string module. (Patch from Kevin Altis)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_4_BRANCH@18718 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

wxPython/demo/GridCustEditor.py

@@ -2,6 +2,7 @@
 from wxPython.wx import *
 from wxPython.grid import *
 
+import string
 #---------------------------------------------------------------------------
 class MyCellEditor(wxPyGridCellEditor):
     """
@@ -143,7 +144,7 @@ class MyCellEditor(wxPyGridCellEditor):
         elif key < 256 and key >= 0 and chr(key) in string.printable:
             ch = chr(key)
             if not evt.ShiftDown():
-                ch = string.lower(ch)
+                ch = ch.lower()
 
         if ch is not None:
             # For this example, replace the text.  Normally we would append it.