Core/Misc: Fixed player corpse looting, added player corpse loot and some more

Port From (https://github.com/TrinityCore/TrinityCore/commit/89f728cd5b6ae3041fdae3c853ac4b0ac5f0a848)

Source/Game/Entities/Creature/Creature.Fields.cs

@@ -93,7 +93,6 @@ namespace Game.Entities
         public ObjectGuid lootingGroupLowGUID;                         // used to find group which is looting corpse
         ObjectGuid m_lootRecipient;
         ObjectGuid m_lootRecipientGroup;
-        ObjectGuid _skinner;
     }
 
     public enum ObjectCellMoveState

Source/Game/Entities/Creature/Creature.cs

@@ -940,8 +940,7 @@ namespace Game.Entities
         }
         public void ResetPickPocketRefillTimer() { _pickpocketLootRestore = 0; }
         public bool CanGeneratePickPocketLoot() { return _pickpocketLootRestore <= Time.UnixTime; }
-        public void SetSkinner(ObjectGuid guid) { _skinner = guid; }
-        public ObjectGuid GetSkinner() { return _skinner; } // Returns the player who skinned this creature    
+        public ObjectGuid GetLootRecipientGUID() { return m_lootRecipient; }
 
         public Player GetLootRecipient()
         {
@@ -958,7 +957,7 @@ namespace Game.Entities
             return Global.GroupMgr.GetGroupByGUID(m_lootRecipientGroup);
         }
 
-        public void SetLootRecipient(Unit unit)
+        public void SetLootRecipient(Unit unit, bool withGroup = true)
         {
             // set the player whose group should receive the right
             // to loot the creature after it dies
@@ -980,9 +979,14 @@ namespace Game.Entities
                 return;
 
             m_lootRecipient = player.GetGUID();
-            Group group = player.GetGroup();
-            if (group)
-                m_lootRecipientGroup = group.GetGUID();
+            if (withGroup)
+            {
+                Group group = player.GetGroup();
+                if (group)
+                    m_lootRecipientGroup = group.GetGUID();
+            }
+            else
+                m_lootRecipientGroup = ObjectGuid.Empty;
 
             AddDynamicFlag(UnitDynFlags.Tapped);
         }