This patch adds support for py3k in base85.c. This is accomplished by including
a header file responsible for abstracting the API differences between python 2
and python 3.
Python 2.5 doesn't like it when we mix str objects and the "t#" format
in PyArg_ParseTuple. Change it to use "s#". Tested with python 2.3, 2.4
and 2.5.