player adjustable TOT offsets

[DanAlbert]

Flight plans have a TOT offset property that adjusts their TOT relative to the package's. There are default offsets for some mission types like SEAD. I meant to expose this to the UI ages ago but apparently never remembered to do so.

[Starfire13]

This would be very handy because the necessary offset for a SEAD flight with HARMs and a SEAD flight with TALDs is very different. 🙂