Adds false bottom briefcases and an IAA traitor item.

As inspired by an anon in the general:
False bottom briefcases! Use a screwdriver to pop open a secret panel, which allows you to store an item that's invisible to a quick search. If you store a gun in the bottom, you can fire it by waving the briefcase angrily at another person.

The IAA gets a traitor item which is meant to be a useful assassination tool in the right hands: a false bottom briefcase with a starting SMG. Stealthy, but a pain to reload or put on burstfire since it's normally trapped in the briefcase. 6 TC, since it's a good weapon.
I think it adds readability, and stops the mistake in the future of someone coming along and thinking these references lack articles before putting one in without the macro. Sure, it's not necessary, but it doesn't hurt to have.