Document the wxPython 3.x version requirement

Author: JorjMcKie

examples/PDF_OLedit.py

@@ -46,6 +46,7 @@
         | PDFBild: Bitmap image of pdf page       |
         +-----------------------------------------+
 
+Please note that you need a wxPython version 3.x for this to work.
 '''
 import os
 import tempfile
@@ -866,4 +867,4 @@ def make_pdf(dlg):
     else:
         wx.MessageBox("Cannot edit encrypted file\n" + infile,
                       "Encrypted File Error")
-        
+