Fix (some) journey durations with de_db

- For journeys arriving at a given time the de_db script returned journeys
sorted by arrival => But to guess dates correctly they should be sorted
by departure
- Sorting journeys by departure for de_db by adding an URL parameter to the
journey URL
- Print a debug message if a calculated duration is negative
- Add date from scripts also if dayAdjustment isn't used (the date values from
the scripts simply weren't used in such cases)