fix for tire smoke staying on

+ lowlands, nakoja, rampant, and sirocco - fixed misc. places where you could get stuck or enter an antiportal.

+ autoturrets now use scott's new low-particle version of their muzzleflash. If the user is seeing a lot of them, this should significantly improve performance.

+ optimized particles for autoturrets

+ fix for one special case that might potentially cause vehicle turrets to be misplaced (though I have never seen it happen because of this)

+ improvements to stationary turret replication and accuracy.

+ fix for roundhouseturret not taking radiusdamage sometimes.
Another small optimization that reduces calls to moveautonomous.