Remove magic number in calculating whether an industry may be within supply range of a station
Add function to estimate industry production over time
Add function to return the best-case travel time for a vehicle
Estimate production for the vehicle travel time to a station and add it to the stations supply weight.
Fix: min. number of order history is 1 to avoid complaining OpenTTD

OpenTTD complains about not enough orders if there is only 1 order in the
order list.