One-Way Windows

Created by: Shadowmech88

A window can now be turned into a one-way window by using a sheet of plastic on it. The plastic can be pried off with a crowbar, turning them back into regular windows. One-way windows obstruct a player's view from one side, but allow them to see through from the other.

One-way windows block night vision goggles and thermals, but not X-ray vision. They also don't block sound and, while I would like them to, I'm not sure how to go about that. They also don't prevent right-clicking to see the contents of a tile, and I am again not sure how to fix that.

The window's dir affects the directions from which it blocks vision, even for full windows. When building one-way windows, face the window toward the direction from which you want it to be transparent. Full windows have a new verb that allows players to manually set their direction, so that they can access the window's diagonal directions, since this PR gives diagonal windows an actual gameplay difference from cardinal windows. Window smoothing doesn't seem to be affected.

For mapping purposes, regular windows can be made into one-way windows by toggling their one_way var.

I'll add these to the Interrogation room once they're merged.