Small Fixes

FIXED:

• Fixed an issue with structures pasting structure voids
• Fixed an issue with tag of expression throwing an error when NBT is null

CHANGED:

• Changed file NBT to support .nbt files

ADDED:

• Added an expression to get a UUID as an int array or least/most bits (used for NBT strings)
• Added an effect to open a sign’s GUI to the player, allowing them to edit a sign