Subtracts two objects from another
-=op_SelfAddition(other)table = {
	a = 10,
	op_SelfAddition = function(other)
	{
		table.a = table.a - other.a
		return table
	}
}
o = {
	a = 9,
	op_SelfAddition = function(other)
	{
		o.a = o.a - other.a
		return o
	}
}
table -= other //table.a == 1