[Feature] Penetratable objects

[DerpyNewbie]

Currently projectiles never go thru objects

Some objects such as sponges/trees leaves should be penetrable by some kind of percentage

Penetration should result in these

• Complete stop, projectile will not penetrate.
• Slowed down penetration, projectile will penetrate but with reduced speed.
• Critical penetration, projectile will penetrate without slowing down.

All these (pseudo)probability should be configurable by each.

Because each projectile has no way of sending penetration information just in time,
using total shot count in Gun to determine which projectile will penetrate, should be the way to implement this.