If items have a common "stackfamily" property in definition, then
they combine stacks; name and metadata are effectively ignored and
any name is considered acceptable for the combined stack name.
This is used by Lux to allow it to stack naturally instead of the
player having to lay them out spaced on the ground to "cool" them
all to the same level, since all Lux changes dynamically anyway.
- Intercept /give commands.
- Provide an API for giving the player an item and inserting it
into the inventory in the right place(s).
- Change the fill order. We try to fill the current slot first,
the continue to the right to the end of the bar, and then
finally work our way left to the beginning. I think this fill
order should be most comfortable, in terms of having items tend
to fall close to the cursor.
