This is the first step in a larger project to add play/pause buttons to
the Liberation UI so the mission can be generated at any point.
docs/design/turnless.md describes the plan.
This adds an option to fast forward the turn to first contact before
generating the mission. None of that is reflected in the UI (for now),
but the miz will be generated with many flights in the air.
For now "first contact" means as soon as any flight reaches its IP. I'll
follow up to add threat checking so that air-to-air combat also triggers
this, as will entering a SAM's threat zone.
This also includes an option to halt fast-forward whenever a player
flight reaches a certain mission-prep phase. This can be used to avoid
fast forwarding past the player's startup time, taxi time, or takeoff
time. By default this option is disabled so player aircraft may start in
the air (possibly even at their IP if they're the first mission to reach
IP).
Fuel states do not currently account for distance traveled during fast
forward. That will come later.
https://github.com/dcs-liberation/dcs_liberation/issues/1681
