Class-dependent pickups 4.0

Changelog

• Minimum ZScript version raised to 4.12.0.
• When spawned in the world, the pickups will now actually be spawned, but visible only to the relevant player classes. This means that instead of copying the first sprite from the target pickup, the pickups will copy everything, including animation, brightmaps, 3D models, etc. Note, the pickups spawned this way will never respawn.