Python 3.7.0 compatibility

Fixing bugs that were seen when switching to Python 3.7.0

After some investigation, I learned that the functionality of Python's re.escape() has changed between Python 3.6.5 and Python 3.7.0:

Python 3.6.5:

>>> import re
>>> re.escape('"')
'\\"'

Python 3.7.0:

>>> import re
>>> re.escape('"')
'"'

Also fixing an unrelated bug with Geckodriver automatic downloads. To do this, I switched to using urllib3.