*Add SpellMgr::CalculateSpellEffectAmount function for consistency of effect amount calculations in core

*Remove SpellEntry::CalculateSimpleValue function and use the new cuntion instead
*Remove some workarounds made because of incorrect effect amount calculations
*Since now aura effect amount problems should be gone.

--HG--
branch : trunk

src/server/game/DataStores/DBCStructure.h

@@ -1513,9 +1513,6 @@ struct SpellEntry
     //uint32  spellDescriptionVariableID;                   // 232      3.2.0
     //uint32  SpellDifficultyId;                            // 233      3.3.0
 
-    // helpers
-    int32 CalculateSimpleValue(uint8 eff) const { return EffectBasePoints[eff]+int32(1); }
-
     private:
         // prevent creating custom entries (copy data from original in fact)
         SpellEntry(SpellEntry const&);                      // DON'T must have implementation