Import py27-billiard-2.7.3.30 as parallel/py-billiard.

billiard is a fork of the Python 2.7 multiprocessing package. The
multiprocessing package itself is a renamed and updated version of R Oudkerk's
pyprocessing package. This standalone variant is intended to be compatible with
Python 2.4 and 2.5, and will draw it's fixes/improvements from python-trunk.

* Also it is a fork of the multiprocessin backport package by Christian Heims;
* It includes the no-execv patch contributed by R. Oudkerk;
* And the Pool improvements previously located in Celery;

(rodent)