* Fixes a number of "<function>: not all control paths return a value" warnings on MSVC.
* Introduces the UNREACHABLE global macro and uses it instead of conditionally compiled switch defaults.
* Move cNBTParseErrorCategory from FastNBT.h into FastNBT.cpp to prevent bad calls to message()
* Shears now lose durability when breaking any block
* Leaves don't drop 2 leaves anymore when broken by shears
* Removed the chance to drop saplings or apples when leaves are broken by shears
* Vines can't be attached to ender chests, pistons and redstone repeaters