shared_ptr -> std::shared_ptr

This is one of the first commits in a plan to remove all `using namespace std;` lines in the entire codebase as it is considered anti-pattern today.

Minecraft.World/ChunkTilesUpdatePacket.h

@@ -25,7 +25,7 @@ public:
 	virtual int getEstimatedSize();
 
 public:
-	static shared_ptr<Packet> create() { return shared_ptr<Packet>(new ChunkTilesUpdatePacket()); }
+	static std::shared_ptr<Packet> create() { return std::shared_ptr<Packet>(new ChunkTilesUpdatePacket()); }
 	virtual int getId() { return 52; }
 };