unseen monster messages

- watch messages if you can't see the watch now start "You hear"
- unseen spellcaster messages are shown as "Something", to remove
 some silly message pairs.
- unseen spellcaster that casts at itself causes no message
- recalc vision before spoteffects messsages, to avoid invalid "It"

src/teleport.c

@@ -272,6 +272,7 @@ register int nux,nuy;
 	see_monsters();
 	vision_full_recalc = 1;
 	nomul(0);
+	vision_recalc(0);	/* vision before effects */
 	spoteffects(TRUE);
 	invocation_message();
 }