Configtool: don't assign values to tuples.

Heck, that's simply forbidden. A C compiler had catched this in a
split second at compile time, Python didn't until the faulty code
section was actually executed (a section of code for rare cases).

The simple fix is to replace the old tuple with a changed, new
tuple.

This resolved issue #242.

configtool/communicationspage.py

@@ -56,7 +56,7 @@ class CommunicationsPage(wx.Panel, Page):
     result = Page.getValues(self)
 
     if result['USB_SERIAL']:
-      result['BAUD'][1] = False
+      result['BAUD'] = result['BAUD'][0], False
       result['XONXOFF'] = False
 
     return result