Add _flatten and _cnfmerge to tkinter package (issue #233)

Author: edschofield

src/future/moves/tkinter/__init__.py

@@ -4,5 +4,6 @@
 
 if not PY3:
     from Tkinter import *
+    from Tkinter import _flatten, _cnfmerge
 else:
     from tkinter import *

src/tkinter/__init__.py

@@ -3,6 +3,7 @@
 
 if sys.version_info[0] < 3:
     from Tkinter import *
+    from Tkinter import _flatten, _cnfmerge
 else:
     raise ImportError('This package should not be accessible on Python 3. '
                       'Either you are trying to run from the python-future src folder '