Core: optimize string splitting

- Mainly affects item loading performance
  - Reduces guild loading time a lot

--HG--
branch : trunk

src/server/game/Entities/Item/Item.cpp

@@ -418,10 +418,10 @@ bool Item::LoadFromDB(uint32 guid, uint64 owner_guid, Field* fields, uint32 entr
         need_save = true;
     }
 
-    Tokens tokens = StrSplit(fields[4].GetString(), " ");
+    Tokens tokens(fields[4].GetString(), ' ', MAX_ITEM_PROTO_SPELLS);
     if (tokens.size() == MAX_ITEM_PROTO_SPELLS)
         for (uint8 i = 0; i < MAX_ITEM_PROTO_SPELLS; ++i)
-            SetSpellCharges(i, atoi(tokens[i].c_str()));
+            SetSpellCharges(i, atoi(tokens[i]));
 
     SetUInt32Value(ITEM_FIELD_FLAGS, fields[5].GetUInt32());
     // Remove bind flag for items vs NO_BIND set