Initial convertion of a_Dt to std::chrono

also refactored cWorld::m_WorldAge and cWorld::m_TimeOfDay

src/BlockEntities/DropSpenserEntity.h

@@ -47,7 +47,7 @@ public:
 	virtual ~cDropSpenserEntity();
 	
 	// cBlockEntity overrides:
-	virtual bool Tick(float a_Dt, cChunk & a_Chunk) override;
+	virtual bool Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk) override;
 	virtual void SendTo(cClientHandle & a_Client) override;
 	virtual void UsedBy(cPlayer * a_Player) override;