module documentation

Internal threadpool library for zenmaster.

Adapted from U{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

Class MarkedThreadPool Flexible thread pool class. Creates a pool of threads, then accepts tasks that will be dispatched to the next available thread.
Class ThreadPoolThread Pooled thread class.