Halve all armour values

This seems like a good start. At least now when I put on light survivour gear and stand 1 tile away from a turret, I actually die after getting shot a dozen times.
Update layering

Make layering penalties consistent with master branch for testing purposes.
bugfix

I HATE SEMICOLONS
Merge pull request #7773 from Izicata/patch-4

Halve all armour values