Core/Groups: Move all function definition from .h to .cpp

Core/Groups: Remove Group.h dependency from any .h file

--HG--
branch : trunk

src/server/scripts/Outland/shadowmoon_valley.cpp

@@ -43,6 +43,7 @@ EndContentData */
 
 #include "ScriptPCH.h"
 #include "ScriptedEscortAI.h"
+#include "Group.h"
 
 /*#####
 # mob_mature_netherwing_drake

src/server/scripts/Outland/terokkar_forest.cpp

@@ -35,6 +35,7 @@ EndContentData */
 
 #include "ScriptPCH.h"
 #include "ScriptedEscortAI.h"
+#include "Group.h"
 
 /*######
 ## mob_unkor_the_ruthless