Introduce a spell enum, and use it everywhere for PC spellcasting

- Monster spellcasting is untouched
- Also updated the spells documentation, which had some old information from Exile III and omitted a lot of ranges.

osx/boe.combat.h

@@ -53,8 +53,8 @@ bool out_monst_all_dead();
 void end_combat();
 bool combat_cast_mage_spell();
 bool combat_cast_priest_spell();
-void start_spell_targeting(short num);
-void start_fancy_spell_targeting(short num);
+void start_spell_targeting(eSpell num, bool freebie = false);
+void start_fancy_spell_targeting(eSpell num, bool freebie = false);
 void spell_cast_hit_return();
 void process_fields();
 void scloud_space(short m,short n);