Fix bug: change _rangeEnd to today

[hackolein]

Change the _rangeEnd Date to today, because it can not be empty. It's the fallback, if there is no rangeEnd is given.

[thelfensdrfer]

This confirms better with the documentation of the paremter Leave this parameter empty to request all data from $rangeStart until now, but $this->_date = $rangeStart; was valid too. It only set the range to one day, the start day.

[hackolein]

Ok, but when I left the parameter blank, then I get the following error message back:
{
"result": "error",
"message": "Das Datum '2014-12-10,' ist keine korrekte Zeitspanne. Es sollte das folgende Format haben: 'lastN', 'previousN', 'YYYY-MM-DD,YYYY-MM-DD'"
}

With the API call: "... period=range&format=json&language=de& ... &date=2014-12-10,"

But, now it works 👍

[thelfensdrfer]

Ok this is strange, the start range should be copied to the end range...but great that it works now!