Ai player utility

helper functions for AI: testing if an object is in line of sight (and optionally if it's enabled), if a point is clear, and if an object is within a given angular field of view (optionally specified beyond a stock 45 degrees, as well as optionally checking if the target is enabled)
I think using `getEyeTransform` would be a better way to go here, as in the original code. I guess this does answer the question of whether the AI can successfully _shoot_ a particular target. Which is handy. I'm torn, though I think for now we should stick with the existing definition and think about revising it or adding a way to use the muzzle transform instead if desired.