Magic numbers cleanup:

- Replace many magic numbers with constants
- Use enum for vehicle flags/seat flags
- Correct structure for ItemRandomSuffixEntry

--HG--
branch : trunk

src/server/game/Entities/Unit/Unit.cpp

@@ -2742,7 +2742,7 @@ SpellMissInfo Unit::MagicSpellHitResult(Unit *pVictim, SpellEntry const *spell)
     if (!IsPositiveSpell(spell->Id))
     {
         bool bNegativeAura = false;
-        for (uint8 i = 0; i < 3; ++i)
+        for (uint8 i = 0; i < MAX_SPELL_EFFECTS; ++i)
         {
             if (spell->EffectApplyAuraName[i] != 0)
             {
@@ -4191,7 +4191,7 @@ void Unit::RemoveArenaAuras(bool onleave)
     {
         AuraApplication const * aurApp = iter->second;
         Aura const * aura = aurApp->GetBase();
-        if (!(aura->GetSpellProto()->AttributesEx4 & (1<<21)) // don't remove stances, shadowform, pally/hunter auras
+        if (!(aura->GetSpellProto()->AttributesEx4 & SPELL_ATTR_EX4_UNK21) // don't remove stances, shadowform, pally/hunter auras
             && !aura->IsPassive()                               // don't remove passive auras
             && (!(aura->GetSpellProto()->Attributes & SPELL_ATTR_UNAFFECTED_BY_INVULNERABILITY) || !(aura->GetSpellProto()->Attributes & SPELL_ATTR_UNK8))   // not unaffected by invulnerability auras or not having that unknown flag (that seemed the most probable)
             && (aurApp->IsPositive() ^ onleave))                   // remove positive buffs on enter, negative buffs on leave
@@ -11191,7 +11191,7 @@ bool Unit::IsImmunedToSpell(SpellEntry const* spellInfo)
                 return true;
     }
 
-    for (int i=0;i<3;++i)
+    for (int i = 0; i < MAX_SPELL_EFFECTS; ++i)
     {
         // State/effect immunities applied by aura expect full spell immunity
         // Ignore effects with mechanic, they are supposed to be checked separately