The poison system is so far quite simple, but can be expanded by wizards
in many ways, since the standard poison_effect object is quite simple.  It
should be noted that the poison_effect object is only the agent of
damage.  Another object must give this object to the player, and start
it.

The main function of the poison object is to repeatedly call a function
until a time limit has expired.  To support this, the object is made
autoloading.  This prevents the players from quitting to rid themselves
of the poison.  Only the remaining time is stored, not the original time
limit.

Damage is repeatedly applied to the player until he is dead or the time
limit is lifted.  There are four types of poison damage supported.  Hit 
points, fatigue and mana may all be reduced, by a maximum amount supplied 
by the wizard.  Stats may be reduced as well.  Stats are only reduced 
temporarily, and only by one point per "hit."  A given poison might hit 
the player quite often, or very rarely, depending on the setings.

It is hoped that this will cover most common poison situations, but if
needed, all kinds of effects may be achieved by replacing the
damage_player() function.  For example, the poison can be made quite 
deadly by actually killing the player upon the timeout period expiring 
(or in the damage_player routine, if more randomness is desired.)  

The method in which the poison is activated can be widely varied.
Possibilities include poisoned weapons, poison stings and bites, and poison
potions.  Multi-stage poisons can be made where no damage is done unless
another poison type is also there.

ANTIDOTES

Each poison must have a type.  An antidote can only apply to the correct
poison type.  To test for poison, one can call query_poison_type().  If
this function is defined, the object is poison.  Type "all" cures all 
poison.  Any other poison type must match exactly. If you don't set the
type of your poison it will be set to "standard".

To actually cure the poison, call poison_effect->cure_poison(eff).  This
tells the poison that a cure of effectiveness 'eff' was tried on it.
This will cure, depending on a formula involving the strength of the
poison.  The success of the cure is returned.