Buffers now have one buffering ItemStack, so they don't spit items out on the ground if there's no output.
Start of disguising block extenders as other blocks
 * Use the linker to select the block type you want to disguise as and then right click a block extender to disguise it as the linked block

Still to do:
 * Make it draw the normal block extender face when not disguised as anything (should be as simple as creating a  block icon for the block extenders as if it were a normal opaque cube block)
 * Figure out a good system for setting and clearing disguises (should the linker be used or not?)
 * Fix weird floating artifacts showing up when disguised as certain things (dirt I know is an issue)
 * Fix the grass block disguise's sides/bottom drawing as incorrectly colored (this is a frustratingly difficult task, because grass block rendering does some checks that are really tough to simulate without actually being a grass block)