Module threadpool

source code

Internal threadpool library for zenmaster.

Adapted from http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/203871

Added a 'marker' to tasks so that multiple tasks with the same marker are not executed. As we are using the thread pool for i/o tasks, the marker is set to the i/o name. This prevents a slow i/o for gobbling up all of our threads