Username/password incorrect with special characters.

[LogicallyUnfit]

Receiving a Key Error

Traceback (most recent call last):
  File "Z:\scriptpath\qrztest.py", line 24, in <module>
    qrzinfo = qrz.callsign("K8MRD")
  File "C:\PythonPath\lib\site-packages\qrz\qrz_query.py", line 51, in callsign
    self._get_session()
  File "C:\PythonPath\lib\site-packages\qrz\qrz_query.py", line 44, in _get_session
    self._session_key = raw_session['QRZDatabase']['Session']['Key']
KeyError: 'Key'

I dug a little to find that this is thrown when a 'Username/password incorrect' error is sent under the session key, This is apparently also sometimes thrown with correct passwords if they contain specific special characters such as ?@#$%&

I can send a pull request with my fix if you'd like.

there is also a warning from connectionpool for InsecureRequestWarning, not sure if that's new or not?