fix #H4275 - blinded, stunned, confused timers

Blindness due to face covered by pie was ignored for several cases
of magically curing blindness--cleaning the face seems better than
adjusting timeout to account for u.ucreamed for those cases.  A few
instances of taking stun or confusion damage overrode existing stun
or confusion rather than increasing it.  Plus a copy/paste mistake
for dual stun+confusion when casting an expired spell.

There was also a suggestion that vomiting when already nauseated
should decrement the timer instead of increasing it.  But there is a
negative effect for as long as it's in effect, so I left that as is.

src/sit.c

@@ -184,6 +184,7 @@ dosit()
                 if (u.uhp >= (u.uhpmax - 5))
                     u.uhpmax += 4;
                 u.uhp = u.uhpmax;
+                u.ucreamed = 0;
                 make_blinded(0L, TRUE);
                 make_sick(0L, (char *) 0, FALSE, SICK_ALL);
                 heal_legs();