merge javelin and spear skills (trunk only)

Part of "multi-shot throwing proposal" last January.  Unfortunately
some of the bits that I had implemented back then have vanished, so I'm
doing it over from scratch.  There were three main parts:
1) allow multi-shot volley throwing for all stackable weapons (affects
   knives, javelins, spears, and boomerangs; other weapons either don't
   stack or are already multi-shot);
2) make worm teeth and crysknives be stackable like ordinary knives;
3) merge spear and javelin skills, so that allocating skill points to
   their use becomes more attractive and they might get used more.
This patch only does #3.

     Since the monk skill set shrinks by more than any of the other roles,
I bumped max skill for escape spells (haste self, invisibility, jumping,
levitation, and teleport away) from basic to skilled; that's the only
skill adjustment included here.  For the couple of roles had different
max values for spear and javelin skill; this keeps the higher of the two.

src/mthrowu.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)mthrowu.c	3.5	2006/03/29	*/
+/*	SCCS Id: @(#)mthrowu.c	3.5	2006/12/14	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -747,7 +747,7 @@ int whodidit;	/* 1==hero, 0=other, -1==just check whether it'll pass thru */
 
 		hits = (oskill != -P_BOW  && oskill != -P_CROSSBOW &&
 			oskill != -P_DART && oskill != -P_SHURIKEN &&
-			oskill != P_SPEAR && oskill != P_JAVELIN &&
+			oskill != P_SPEAR &&
 			oskill != P_KNIFE);	/* but not dagger */
 		break;
 	    }