a single station.
Thanks to: Truelight for the saveload code, Darkvater and Hackykid for
network testing and Tron for proof-reading 1500 lines of diff.
-Codechange: renamed all 'schedule' stuff to 'order(list)'
-Codechange: moved all order-stuff to order_cmd.c / order.h
-Codechange: vehicles that share orders are now linked to eachother
with next_shared/prev_shared in Vehicle
Developers: please use AssignOrder to assign data to an order. If not,
you _WILL_ make the save-routine to assert!
-Codechange: removed next_in_chain_old, and saved ->next for Vehicles
(and bumped savegame revision for that to version 4.4)
-Codechange: Added _sl.full_version, which has both major and minor version
an uint8 till the savegame version is bumped to version 5. Then it works
automaticly as a fully uint16. So _stations[] can not be increased till
after the bump!!
-Fix: added debug code to autosave cause it is buggy in multiplayer (does not remember settings; takes them from _opt instead of _new_opt (or vice versa)).