Revert "shared_ptr -> std::shared_ptr"

This reverts commit 7074f35e4b.

Minecraft.World/HellSandTile.h

@@ -7,5 +7,5 @@ class HellSandTile : public Tile
 public:
 	HellSandTile(int id);
 	virtual AABB *getAABB(Level *level, int x, int y, int z);
-	virtual void entityInside(Level *level, int x, int y, int z, std::shared_ptr<Entity> entity);
+	virtual void entityInside(Level *level, int x, int y, int z, shared_ptr<Entity> entity);
 };