Billiard

--------------------

- Now always cleans up after ``sys.exc_info()`` to avoid
cyclic references.

- ExceptionInfo without arguments now defaults to ``sys.exc_info``.

- Forking can now be disabled using the
``MULTIPROCESSING_FORKING_DISABLE`` environment variable.

Also this envvar is set so that the behavior is inherited
after execv.

- The semaphore cleanup process started when execv is used
now sets a useful process name if the ``setproctitle``
module is installed.

- Sets the ``FORKED_BY_MULTIPROCESSING``
environment variable if forking is disabled.

--------------------

- Added `billiard.ensure_multiprocessing()`

Raises NotImplementedError if the platform does not support
multiprocessing (e.g. Jython).

--------------------

- PyPy now falls back to using its internal _multiprocessing module,
so everything works except for forking_enable(False) (which
silently degrades).

- Fixed Python 2.5 compat. issues.

- Uses more with statements

- Merged some of the changes from the Python 3 branch.

--------------------

- Now installs on PyPy/Jython (but does not work).

--------------------

- Python 2.5 support added.

--------------------

- Updated from Python 2.7.3

- Python 2.4 support removed, now only supports 2.5, 2.6 and 2.7.
(may consider py3k support at some point).

- Pool improvements from Celery.

- no-execv patch added (https://bugs.python.org/issue8713)