Prefer importlib over imp (#513)
Prefer importlib over imp (#513)

* Use importlib when available

imp was deprecated as of Python 3.3, and can cause some strange
issues when import logic has been overridden, such as with
pyinstaller: https://github.com/pyinstaller/pyinstaller/issues/3429

* More carefully import modules to be monkey-patched

Keep these modules and _strptime itself seperate

scrapinghub/dateparser