feat(core): Ensure that all actions are compared to fixed point in time (#1236) (#1458)

i.e. world update start

src/server/game/Time/GameTime.h

@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2016+     AzerothCore <www.azerothcore.org>, released under GNU GPL v2 license: https://github.com/azerothcore/azerothcore-wotlk/blob/master/LICENSE-GPL2
+ * Copyright (C) 2008-2016 TrinityCore <http://www.trinitycore.org/>
+ * Copyright (C) 2005-2009 MaNGOS <http://getmangos.com/>
+ */
+ 
+#ifndef __GAMETIME_H
+#define __GAMETIME_H
+
+#include "Define.h"
+
+#include <chrono>
+
+namespace GameTime
+{
+    // Server start time
+    time_t GetStartTime();
+
+    // Current server time (unix) in seconds
+    time_t GetGameTime();
+
+    // Milliseconds since server start
+    uint32 GetGameTimeMS();
+
+    /// Current chrono system_clock time point
+    std::chrono::system_clock::time_point GetGameTimeSystemPoint();
+
+    /// Current chrono steady_clock time point
+    std::chrono::steady_clock::time_point GetGameTimeSteadyPoint();
+
+    /// Uptime (in secs)
+    uint32 GetUptime();
+
+    void UpdateGameTimers();
+};
+
+#endif