Additional AI code, including stuff taking advantage of glide and sidethrust. Includes: Flag for allowing fighters to dodge vertically as well as horizontally, "stalemate detection" to help AI break out of circle fights and other stalemate situations, "glide attack" where AI fighters will use glide to fly away while shooting back at you, "circle strafe" where AI fighters will use sidethrusters to jink around while shooting, and an (incomplete) version of "glide strafe" that allows fighters/bombers to use glide to attack capital ships. All new stuff is off by default, and can be turned on with AI_Profiles flags.
