Improved readability of the run method in the queues.py and a few additions to .gitignore

I'm not 100% happy with "continue_running", but I haven't come up with a better variable name. I feel like it is better than re-purposing processed. Initializing processed = None feels more intuitive and at the end of each loop we can re-evaluate whether or not to continue running. Always relying on a break to exit a loop never feels quite right.

I also added *.pyc and .DS_Store to the .gitignore file for the slackers that don't have them globally ignored.