Anti-tank gun exit positions are incorrect

[Colin Basnett]

Pretty much all the AT guns have improper exit positions (some put you above the gun or in the gun).

To generate useful exit positions, use the ExitPosTool exec, described with this comment:

// Function to get offset coordinates from nearby vehicle(s) to create/adjust vehicle exit positions (Only works in singleplayer)

[Andrew Theel]

Fixed in 37860c2