Merge pull request #22 from nlevitt/master

whole bunch of changes (already deployed on QA)
only websocket-client-py3==0.13.1 works right with python3 at the moment, see https://github.com/liris/websocket-client/issues/84
configurable max number of instances of chrome simultaneously browsing pages (default=3); close and reopen connection to amqp every 15 minutes (consumer only); increase default browser wait to 60 sec
refactor umbra.py into controller.py and browser.py, improve class names