Core: Add wintergrasp-patch to wintergrasp_cleanup branch - resurrected from an old work-repository, now over as a branch to work on.

Original patch by socolin, cand a ton of contributors :
mathman, joda, spp, silinoron, josh, malcrom, shauren, machiavelli, click, rat, leak, tobmaps, _manuel_, the tcfr team (via socolin), and tons of others for chiming in.

NOTE: THIS IS A WORKING-BRANCH, AND _NOT_ MENT FOR PUBLIC USE OR EVEN CONSIDERED STABLE!

src/server/game/Entities/Player/Player.h

@@ -2378,8 +2378,8 @@ class Player : public Unit, public GridObject<Player>
         Player* GetNextRandomRaidMember(float radius);
         PartyResult CanUninviteFromGroup() const;
         // Battleground Group System
-        void SetBattlegroundRaid(Group* group, int8 subgroup = -1);
-        void RemoveFromBattlegroundRaid();
+        void SetBattlegroundOrBattlefieldRaid(Group *group, int8 subgroup = -1);
+        void RemoveFromBattlegroundOrBattlefieldRaid();
         Group * GetOriginalGroup() { return m_originalGroup.getTarget(); }
         GroupReference& GetOriginalGroupRef() { return m_originalGroup; }
         uint8 GetOriginalSubGroup() const { return m_originalGroup.getSubGroup(); }