UseItemOn

Function:

 * boolean useItemOn(item, x, y, z)

Parameters:

 * item - can be item id/name.
 * x - }
 * y - } Position of tile on witch bot should use given item.
 * z - }

Return value:

 * This function return an boolean indicating if items were succesfuly used. Returns true if success, false if failure.

Description:

 * This function can be used to use item on certain positions. Possible uses are: opening doors with a key, etc.