Fix unittests and affinity issue with child processes

• fixes some Python3 unittests
• fix processor affinity issue with child processes

v0.6.1

Fix cannot upload to PyPI because it can't render markdown as reST

Python 3 compatibility upgrade

• Changes to support python 3

v0.7 Replace prctl dependency with ctypes, and improve error handling with PID files

Our prior use of prctl calls for setting the process death signal (and setting process names in testing) used python-prctl. However, that library is GPL-licensed, and this library is Apache 2.0-licensed. Switched to using our own internal ctypes-based method for those calls.

Also, if a child process didn't start up, and we were expecting it to write a PID file, we had an error reading the non-existent file. Switched to handle this more sensibly and give appropriate explanations.

v0.6 Bugfix don't try to kill already-stopped child processes

This error meant that if a child process had stopped, an attempt to stop it would cause an error. This release only contains a fix for this bug.

v0.5 Bugfix stopping forking child strategy processes

This error meant that if the process hadn't stopped, an attempt to gracefully terminate it would leave it running, but if it had stopped, it would wait for ages. This release only contains a fix for this bug.

v0.4: Handle Windows Job objects better

As of Windows 8 / Server 2012, Job Objects can be nested. This change makes the code more optimistic - attempting to create a Job Object and only raising an exception if it fails.