Revert "Update Python module code"

This reverts commit f39b46f67ab03d0bc96987e9eaca574039589adf.

The latest version of readline.c contains Python 3.4 specific
code (PyMem_RawMalloc). This will need a custom readline.c.
Use a custom readline.c for Python 3.4

Python 3.4 introduced changes to readline.c that are incompatible
with Python 3.3 and earlier (PyMem_RawMalloc). Keep a separate copy
of readline.c for this release, based on the hg 3.4 branch (changeset
ID 89086:3110fb3095a2), while the 3.x readline.c remains at the
existing hg 3.3 branch (changeset ID 89085:6adac0d9b933).

Add code to setup.py to pick the most relevant version of
readline.c and update changelog to reflect this.