Modification notes:

living.c:  modified so that lethargy could be implemented.
Disease can slow someone down.
Also modified so that SYMPTOMS could be applied.

define.h:  disease and symptom type #'s defined, 9 new spells added.

spellist.h:  new spells.
spells.h:  ""

sproto.h: prototyes

archetypes:  diseases added.

treasures:  needle_diseases added, liches/demilich/spectres cause disease.

server/Imakefile:  disease.o added

server/attack.c:  typo fixed, check for infection upon a hit from someone
infected.

server/ericserver.c:  typo fixed.

server/player.c:  diseases removed on death.

server/rune.c:  traps with treasure lists generate treasures (i.e., diseases)
and inject the disease.

server/spell_effect.c:  new spells added, cast_heal modified to reduce symptoms,
cast_cause_disease added,

server/spell_util.c:  new spells added.