Certain configurations of the flight plan cause a crash

[Noiredd]

PEGAS crashes if the resulting flight plan is shorter than 5 items. Problem is on line 480 in pegas_misc.ks.

Another crash occurs if all sequence events occur prior to UPFG activation. Relevant line 406 in pegas_misc.ks.

Fixes seem simple and I'll implement them soon, just posting here to notify that I'm aware of the bugs.