Smooth Creeper

Smooth Creeper alters creeper explosions so that they apply silk touch to all drops and drop all blocks. This makes it easier to patch up creeper craters *and* adds an early-game way to silk touch blocks (although it is a bit messy!).

Note: Dropping all blocks is done by making the `mobExplosionDropDecay‌` gamerule default to `false`. If you are adding this to an existing world, you must manually set the gamerule using the command `/gamerule mobExplosionDropDecay false`