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.

doc/fixes35.0

@@ -268,6 +268,7 @@ include time, user ID, and play mode in paniclog entries
 add oracle and rumor regarding priestly donations
 anti-magic traps have alternate effect on targets who have magic resistance
 the Amulet can be offered to Moloch
+javelins and spears now share the same weapon skill
 
 
 Platform- and/or Interface-Specific New Features