[vehicle management] Cannot create or modify schedule

[Ves]

Starting to look into this branch in order to start creating some GUI, i ran into the very constraining problem that I cannot create or modify schedules. What happens is that the "Schedule window" opens, and entries is nicely added to or removed from the list, but when closing it appears that all new entries are deleted, and old entries in an existing schedule will get back again.
So it seems to be a saving problem somewhere.

[jamespetts]

Thank you for your report: I think that I have now fixed this. I should be grateful if you could re-test.