[8030] Fixed spell 64901 work and related target selection code refactoring. Author: VladimirMangos

* Replace 64904 by 64901 in spellbook and action bars.
    * Implement proper max mana percent buff
    * Implement proper target selection.
    * Move group/raid targets seelction code to functions for reuse code.

--HG--
branch : trunk

src/game/SpellAuras.cpp

@@ -5137,6 +5137,19 @@ void AuraEffect::HandleAuraModIncreaseEnergy(bool apply, bool Real, bool /*chang
 
     UnitMods unitMod = UnitMods(UNIT_MOD_POWER_START + powerType);
 
+    // Special case with temporary increase max/current power (percent)
+    if (GetId()==64904)                                     // Hymn of Hope
+    {
+        if(Real)
+        {
+            uint32 val = m_target->GetPower(powerType);
+            m_target->HandleStatModifier(unitMod, TOTAL_PCT, float(m_amount), apply);
+            m_target->SetPower(powerType, apply ? val*(100+m_amount)/100 : val*100/(100+m_amount));
+        }
+        return;
+    }
+
+    // generic flat case
     m_target->HandleStatModifier(unitMod, TOTAL_VALUE, float(m_amount), apply);
 }