Name: first_inventory - get the first object of an inventory

Syntax:
	object first_inventory(object ob)

Description:
	The first_inventory gets the first object of an inventory of an
	object.

Return value:
	If the object has no inventory, 0 is returned, else an object
	pointer to the first object in its inventory is returned.

See also: efun/next_inventory, efun/all_inventory, efun/present