PR from Tctiancan. Fixed breaking mirecap, scriptorium, polished button, sign, pressure_plate yielded no drops. Axes can break Scriptorium and Hanging Sign faster. Fixed effect icon still displayed on the client after Purity Incense removed the effect. Only Fixed Death Bane Incense and Gloom Incense had opposite effects on undead and non-undead mob. Fixed Observer could not emit a redstone tick on Crucible step change.