Change map-spawned thindows to 3/4 perspective

[MrMagolor]

It doesn't make sense how the windows that are already placed use a different sprite than the ones we build, which is REALLY ANNOYING when I want to repair something.

Of course, this would probably take a VERY long time and most coders hate thindows anyways, so...

And thindows aren't really used much anymore anyways- the main example I can think of is cog1's operating theater.