Fix data not acquired and fair use notice.

This release fixes that after successful login, no data is retrieved.
Also please notice this update in const.py:

######################################################################
##  NOTICE ON FAIR USE:
##  Please do not set this constant below 15 minutes.
##  Softværket who runs the API will impose an IP-ban if fair use
##  is not adhered to.
##
##  The dataset is updated every 24 hours in the morning.
##  The default min. time is to spread out load on the API and still
##  retrieve data.
######################################################################
MIN_TIME_BETWEEN_UPDATES = timedelta(hours=6)

With this update a few few hectic days of updates and bug hunting is hopefully concluded.

Thanks for the very friendly and open response from both eForsyning and Softværket on resolving issue #25