Python 3.2 is not supported, name it PyPy3 instead

...which is Python 3.2 based.

README.md

@@ -29,7 +29,7 @@ Simply install with:
 ### Optional dependencies
 
 * [icalendar][7]      : To print your todo.txt file as an iCalendar file
-                        (not supported for Python 3.2).
+                        (not supported for PyPy3).
 * [prompt-toolkit][6] : For topydo's _prompt_ mode, which offers a shell-like
                         interface with auto-completion.
 * [arrow][8]          : Used to turn dates into a human readable version.
@@ -37,8 +37,7 @@ Simply install with:
                                             window size. This function was
                                             added to the standard library in
                                             Python 3.3 and so is only
-                                            required in older versions of
-                                            Python.
+                                            required for PyPy3.
 * [python-dateutil][10]: A dependency of *arrow*.
 * [mock][11]          : Used for testing. This was added to the standard
                         library in Python 3.3.