Merge pull request #878 from freqtrade/fix_timeframe_issue

fix windows-specific init issue with named tuple

freqtrade/arguments.py

@@ -248,7 +248,7 @@ class Arguments(object):
         :return: Start and End range period
         """
         if text is None:
-            return TimeRange()
+            return TimeRange(None, None, 0, 0)
         syntax = [(r'^-(\d{8})$', (None, 'date')),
                   (r'^(\d{8})-$', ('date', None)),
                   (r'^(\d{8})-(\d{8})$', ('date', 'date')),