Ai smarts

[ferram4]

Lots of changes to the AI to try and make it fight better, though it's probably not finished and requires testing. Includes:

• AI will call for help from nearby friendlies when under fire using a new SetOverrideTarget system
• AI will try to maneuver in the vertical when turning on opponents, generally deciding whether to go up/down based on whether they are under possible threat from the current target
• AI will evade guns by trying to break in towards the threat and make themselves the most difficult target possible
• AI will try to extrapolate the motion of targets based on how long it will take them to turn around
• AI will extend somewhat further when they are set to extend, which makes it more effective in gunfights and generally results in a less steep climb when they do, so they're not as helpless.

Also, bugfix for the gun ripple code not allowing full RoF, instead limiting based on framerate.

[ferram4]

I added some extra code to ensure that AI that are attacking an opponent and simply can't follow it through a turn due to too much speed simply extend. I also added a "target suitability" selection for the standard GetAirToAirTarget method that tries to rate targets based on how close they are and the plane's orientation; this combined with extending allows AI to simply decide to go after another target after passing the one they were engaging.

The only thing I want to try adding next is something to dynamically adjust the extension range based on enemies around the AI. I had a situation where an AI mortally wounded a target, overshot and extended and should have immediately engaged and head-on attacked another target that was 400 m away, but instead extended past it and allowed it to sit on its 6. Then I believe it will be good to be merged.