Initial python3 changes

Mostly just updating libraries, removing string encoding/decoding,
fixing some edge cases. No new functionality was added in this
commit.

lib/osxnotify/registerapp.py

@@ -129,5 +129,5 @@ if __name__ == '__main__':
 
         return app_path, 'App registered'
 
-    except Exception, e:
+    except Exception as e:
         return None, 'Error creating App %s. %s' % (app_path, e)