Icing at startup option and interior temperature settling bug fix

[wlbragg]

There was a environmental temperature delay on startup that affects the interior temperature code programming for the aircraft and the ability to have icing conditions (frost) on the the windows. I may have a way to deal with it. See the fuel heating system in the development version of the AirCrane, (Systems/fuel.xml), and see if that is the kind of delay switch that will help with this issue.