Buzz macros and related stuff

Add macros to convert AD_foo, WAN_foo, and SPE_foo to relative values
for passing to BZ_U_foo and BZ_M_foo macros.

Change some return values in monster spellcasting function from
magic numbers to MM_MISS or MM_HIT.

Make buzzmu consider hero resistances - previously the
monster with innate zapping ray (Angels and Asmodeus) would
just keep doing that attack, but they will now just curse if
it saw the hero resist the attack.

include/objects.h

@@ -1203,6 +1203,7 @@ SCROLL("blank paper", "unlabeled",  0,  28,  60, SCR_BLANK_PAPER),
 #define PAPER LEATHER /* override enum for use in SPELL() expansion */
 SPELL("dig",             "parchment",
       P_MATTER_SPELL,      20,  6, 5, 1, RAY, HI_LEATHER, SPE_DIG),
+/* magic missile ... finger of death must be in this order; see buzz() */
 SPELL("magic missile",   "vellum",
       P_ATTACK_SPELL,      45,  2, 2, 1, RAY, HI_LEATHER, SPE_MAGIC_MISSILE),
 #undef PAPER /* revert to normal material */
@@ -1382,6 +1383,7 @@ WAND("probing",       "uranium", 30, 150, 1, IMMEDIATE, METAL, HI_METAL,
                                                     WAN_PROBING),
 WAND("digging",          "iron", 55, 150, 1, RAY, IRON, HI_METAL,
                                                     WAN_DIGGING),
+/* magic missile ... lightning must be in this order; see buzz() */
 WAND("magic missile",   "steel", 50, 150, 1, RAY, IRON, HI_METAL,
                                                     WAN_MAGIC_MISSILE),
 WAND("fire",        "hexagonal", 40, 175, 1, RAY, IRON, HI_METAL,