Core/Misc: Headers cleanup

Use simple std::string concatenation instead of stringstream to avoid including <sstream> header.

(cherry picked from commit 9c790e231e)

src/server/game/Movement/MovementGenerator.cpp

@@ -22,6 +22,7 @@
 #include "PathGenerator.h"
 #include "RandomMovementGenerator.h"
 #include "WaypointMovementGenerator.h"
+#include <sstream>
 
 MovementGenerator::~MovementGenerator() { }
 

src/server/game/Movement/MovementGenerators/FlightPathMovementGenerator.cpp

@@ -24,6 +24,7 @@
 #include "MoveSplineInit.h"
 #include "ObjectMgr.h"
 #include "Player.h"
+#include <sstream>
 
 #define FLIGHT_TRAVEL_UPDATE 100
 #define TIMEDIFF_NEXT_WP 250

src/server/game/Movement/MovementGenerators/PathMovementBase.h

@@ -19,7 +19,7 @@
 #define PathMovementBase_h__
 
 #include "Define.h"
-#include <sstream>
+#include <string>
 
 template<class Entity, class BasePath>
 class PathMovementBase
@@ -32,10 +32,7 @@ class PathMovementBase
 
         virtual std::string GetDebugInfo() const
         {
-            std::stringstream sstr;
-            sstr << std::boolalpha
-                << "Current Node: " << GetCurrentNode();
-            return sstr.str();
+            return "Current Node: " + std::to_string(GetCurrentNode());
         };
 
     protected:

src/server/game/Movement/MovementGenerators/WaypointMovementGenerator.cpp

@@ -27,6 +27,7 @@
 #include "ObjectMgr.h"
 #include "Transport.h"
 #include "WaypointManager.h"
+#include <sstream>
 
 WaypointMovementGenerator<Creature>::WaypointMovementGenerator(uint32 pathId, bool repeating) : _nextMoveTime(0), _pathId(pathId), _repeating(repeating), _loadedFromDB(true)
 {