Fix the ship requirement for WarmUpIdleShips.
Use RepairSlot.in_use.
Clear a repair slot when completed.
Update ship hitpoint when repair is copmleted.
This is required to handle AutoRepairShips and AutoWarmUpIdleShips correctly.
Actually, ndock KCSAPI is called automatically when ETA has reached. However
usual ship state update KCSAPI (port or ship2) is not necessarily called at the
same time.
Support repair speedchange KCSAPI.