string query_auto_load()

An object that wants to be loaded automatically when the player
logs in, should define this function. There are some important rules about
how to use it:

1. It must not have any weight.

2. It must prevent the player from dropping it.

3. It must be loaded before the player logs in. Otherwise, it will not
   be loaded.

4. query_auto_load() must return a string that is:    file:arg
   The 'file' is the definition that will be cloned. The 'arg' is a string
   that will be sent as argument to the function 'init_arg()'. The 'arg'
   can be an empty string.

5. It must not be an actively usable item, like weapon or armour.

The idea with this feature is that a player can get a curse or membership,
that will stick with him, even if he quits.
The idea is not that the player will save his weapons etc.

Look at /obj/shout_curse.c for an example.