Blocks for Builders

Was doing some post-update backend cleaning up and optimising and caught a number of small issues/model inconsistencies/etc. so here's a quick fix for everything I noticed.

• Added Hay Rug

  Realised Hay should probably have this to match the other Thatch blocks.

• Reworked Pillar Slabs (Thatch and Grimstone Slabs)

  They now behave essentially exactly the same as full pillar blocks, meaning they have a "Y-axis" version that can be used to extend columns in addition to the pre-existing variants. I also reworked Grimstone Tile slabs to make them consistent with this since their previous model kinda made no sense. The only real loss there is there might be very specific niche cases where they'll look slightly worse next to the stairs but otherwise it's a total gain for them as they'll be much more versatile now. The only other general effect of this change is that now these Slabs default to facing towards you when placed, instead of away, for consistency with their Block counterparts over Stairs, but that should be easy enough to get used to.

• Added all BFB Saplings to the Wandering Trader

  Probably should have caught this sooner. Not a huge deal but just added it for parity with Vanilla. And nice if anyone's running BFB in a superflat world?

• Tweaked Bamboo Thatch textures

  The twine holding them together now matches that of the Vanilla Bamboo Raft for consistency.

• Tweaked Palm Raft textures

  Tiny change to add dark spots to the rope where it crosses the lines between blanks, for consistency with the Vanilla raft design.

• Pillar Slabs and Carpets now have the same orientation as Pillar Stairs in the inventory

• Moved Hay Blocks' position in the Creative inventory

• Fixed a handful of Slab blocks' names being "Slabs" as opposed to "Slab"