Adds the /model command, allowing any item to be given any model
Adds QoL features to the movement system: Step up, Boat step up, Coyote time (jump forgiveness), Bedrock bridging, & Bedrock elytra canceling.
Makes parts of the inventory and HUD more useful
Adds slabs, stairs, walls, fences, and more non-full block variants of many vanilla blocks.
Skips the movement check on the server side that causes rubber-banding due to "moved too quickly" or "moved wrongly".
