Pointed Dripstone can break blocks

If a dripstone is pushed against a block it's pointing at, it will break the block. The dripstones should only be able to break blocks that are harvestable with an iron pickaxe. If this feature is added along pointed dripstone sticking to dripstone blocks, then dripstone can be used to build drills that make tunnels, which will be a great inclusion to the Caves & Cliffs Update.