Added missing XComAi.ini data.

Ghosts should be less likely to keep moving when they don't need to now.

Fixed Marksman AI causing them to be too hyper aggressive with movement.

Gave Marksman Penalty Shot: this lets them take more shots early on, at the expense of their aim.

Future proof'd mod: it should be able to handle a hypothetical multiple SITREPs per mission mod, if other raider mods are installed.