Changes:

* Updated to Minecraft 1.15.2
* Added a recipe for the pump (4 iron ingots, 4 blocks of stone, and 1 bucket)
* Prevented "slab" facades from overlapping.
* The "-all" jar is now 25% smaller (~750 KB rather than 1MB)
    This is due to an alternative approach to compression:
    now we decompress the jar-in-jar and just store them, which
    allows the containing jar to do a better job of compressing
    the contents.

Bug Fixes:

* Fixed an incompatibility with nbt-crafting.
