Core/Unit: Big cleanup in Unit::CalcAbsorbResist

Core/AuraScript:
	Fix compile time check for AuraScript functions
	Remove AuraApplication from hook functions parameter list, use GetTarget() and GetTargetApplication() instead
	Add OnEffectAbsorb hook
Scripts: move handlers of Spell Deflection, Savage Defense, Primal Tenacity, Nerves of Steel, Astral shift from core to scripts.

--HG--
branch : trunk

src/server/scripts/Spells/spell_hunter.cpp

@@ -357,14 +357,14 @@ public:
             return true;
         }
 
-        void HandlePeriodic(AuraEffect const * aurEff, AuraApplication const * aurApp)
+        void HandlePeriodic(AuraEffect const * aurEff)
         {
             PreventDefaultAction();
             if (aurEff->GetAmount() > 0)
                 return;
 
             uint32 spellId = SPELL_SNIPER_TRAINING_BUFF_R1 + GetId() - SPELL_SNIPER_TRAINING_R1;
-            Unit * pTarget = aurApp->GetTarget();
+            Unit * pTarget = GetTarget();
             if (!pTarget->HasAura(spellId))
             {
                 SpellEntry const * triggeredSpellInfo = sSpellStore.LookupEntry(spellId);