Fix player who shoots Combine Ball being launched toward to the direction of moving platform while the player is on the platform

Add toggle for SWEP owner immune from explosion

Hide ammo count of Admin Weapon

They use Pistol ammo internally, but don't use it at all. No need to display useless information.

To mitigate EDICT problem, SC Admin Weapon will now use pooled 'env_explosion' entity.

Note that 'env_explosion' is still expensive entity, so spamming it can still crash GMod in some maps.

Using VPhysics Jolt can ease this issue, but this will create another issue when using Hammer++.