Py3 fixes
Maybe fix gc cleanup error (Closes celery/celery/#993)
Pool: Always use _kill for Win compat on Py2.5.  Closes #32
Updates Changelog
Bumps version to 2.7.3.19
Fixes name error in process.py
use os.kill instead of signal.signal which sets up a handler instead
use os.kill instead of signal.signal which sets up a handler instead
Restart limits should not be enabled if maxR is not set
self._value is an ExceptionInfo, we can't raise it

Because billiard wraps exceptions in ExceptionInfo, we can't just raise the ._value that is returned from a worker.  We need to raise the ._value.exception.
Bumps version to 2.7.3.20 and updates Changelog
flakes
Bumps version to 2.7.3.21 and updates Changelog
Merge branch '2.7'

Conflicts:
	CHANGES.txt
	billiard/__init__.py
	billiard/_connection.py
	billiard/connection.py
	billiard/dummy/__init__.py
	billiard/pool.py
	billiard/util.py