Fix for writing braintree as unicode

Author: keiffster

src/programy/parser/pattern/graph.py

@@ -256,7 +256,7 @@ def save_braintree(self, bot, clientid, filename, content):
             braintree += '<aiml>\n'
             braintree += self.root.to_xml(bot, clientid)
             braintree += '</aiml>\n'
-            with open(filename, "w+") as dump_file:
+            with open(filename, "w+", encoding="utf-8") as dump_file:
                 dump_file.write(braintree)
         else:
             if logging.getLogger().isEnabledFor(logging.ERROR):