Update pytest requirements and a few other things:
- Updated requirements:
pytest>=4.2.0,pytest-xdist>=1.26.1,flake8==3.7.3. - Add option to raise a Python Exception immediately when specifying an invalid proxy string, rather than waiting to display a warning message at the end of the test run (without using a proxy server). Usage:
--proxy=[PROXY_STRING]. - Disable Chrome local_discovery pop-up notifications, such as "New printer on your network".