Move some hard-coded string arrays into data files.

Random epitaphs, engravings and hallucinatory monsters now
live in text data files.

src/muse.c

@@ -88,7 +88,7 @@ struct obj *obj;
 			if (vis) {
 			    pline("As %s opens the bottle, an enormous %s emerges!",
 			       mon_nam(mon),
-			       Hallucination ? rndmonnam() : (const char *)"ghost");
+			       Hallucination ? rndmonnam(NULL) : (const char *)"ghost");
 			    pline("%s is frightened to death, and unable to move.",
 				    Monnam(mon));
 			}