HUD cleanup

[colingeniet]

Leftovers from the merge, for AJS HUD

• In nav/landing mode, shut off at 15° flight path angle, back on at 12°.
• Waypoint ETA computation in the route manager is stupid (doesn't take heading in account). Need a custom one.
• There should be a flight director feature during the turn at waypoint change. Reference point doesn't blindly indicate target heading. 15° from target heading, it starts to indicate to exit the turn.
• Disable waypoint change in mode ANF / SPA
• Find how to stop the reference point from turning wildly just before passing a waypoint.
• Combat HUD:
  • Target ring in aiming modes. (need to find another symbol for the Rb 75 seeker)
  • Rb 04: reference alt 240m
  • Bomb: try to make it slightly less bad
  • Rb 75 is missing the pull-up warning.
  • IR-Rb: try to implement radar ranging?