Makes combat tables for items refer back to their source item.
Adds a self property to o.combat and o.special_combat that refers back to item's full table. Combat tables tend to get passed around through various functions and callbacks and it can be difficult to connect a combat table to a full object. This makes the link two-way (o.combat.self == o).
This doesn't break saves, but any functionality dependent on the link will require a new save, as it only applies to newly generated items.
Merged
by 
The changes were merged into master. The source branch has been removed.
