Sneaking now prevents falling more than 0.6b (previously 1b)
Blocks
Added Shulker Box - 1×1×1 collision box, can extend by 0.5b when opened with right click.
The extension increases and decreases by increments of 0.05b every tick.
The shulker box can only be opened if it doesn't end up intersecting with another collision box.
Interestingly, the opening starts with a surplus of 0.01b, which means the player is actually pushed 0.51b. At the end of the opening animation, the extension's length is brought back to 0.5b.