Stable Handling and Gun Mod

This mod makes several changes to make the flight model and gunplay feel more stable:

- Planes will have a lower instant turn rate (less sensitivity to small input)

- Planes will "drift" after releasing the stick (instead of forcing the player to overshoot turns)

- High-G turn delay lowered

- Post-stall maneuver speed limit extended to 800 kph

Gun bullet velocity is also increased to reduce erratic reticle movements. Damage is slightly increased.