* Autostand for the AI.
* Introduced AI_CalcShotDamage.
* Better #define name?
* Allow the LUA AI access to shot checking AI functions.
* Improved AIL_positionshoot.

* Now will check that it's actually *possible* to shoot from there...
* Renamed AI_SearchBestTarget to AI_FindBestFiredef.

* Because that's what it's actually doing...
* [AI] vis check less.

* Check visibility once per target (instead of one per wepon per target,
  not that they usually carry more than one weapon, but still).
* Also only do a vis test if the target isn't already visible (for team)
* Side efect of the above: the AI is now capable of doing "indirect fire"
  not that they have many ways to take advantage of it anyway...
* Replaced magic number.
* Give access to AI_CalcShotDamage.
* Reaction fire is automatic don't include it here.
* Improved actorL_shoot.
* Don't try to use the LUA AI with g_aihumans.

* Human players' actors don't have a LUA state.