Issue description
In 1.8.3 you added many more variables (world and dimension variables and block and entity nbt variables ). Now a lot of things are possible :D
It would be cool if you add item nbt variables too. We could make items that change form after a few time, items that are bound to locations, special enchantments and much more.
One can not add NBT directly to item, but we can add itemstack NBT procedure blocks.