Added GS out of range flag to Instruments-3d/vor.
Century III upgrades
1. Implemented the two 20 sec checks for GS arm documented in the autopilot POH page 30.
2. Fixed bug that made GS capture not work if the ALT switch was turned off for a few moments to do a step-down approach.
"I have been working with Torsten Dryer to model
these three autopilots that are very common in aircraft manufactured in
the 1960s through the late 1980s. The Altimatic IIIc in the SenecaII is
a variation on the Century III and uses the same nasal model."
mf: these should be in cvs since a while; somehow I missed them, sorry
