The result of IDropoffManager.getDropoffItemHandler() is currently being ignored, causing all tiles implementing IDropoffManager to no longer work with the dropoff button.

ret is set but never returned: https://github.com/Vazkii/Quark/blob/8b98a4f5a638af658eb25e1db19b9c4b1444c15f/src/main/java/vazkii/quark/base/handler/DropoffHandler.java#L86-L91

Related to #744 / TwelveIterationMods/CookingForBlockheads#255