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.Client/Common/Tutorial/CompleteUsingItemTask.h

@@ -16,5 +16,5 @@ public:
 	CompleteUsingItemTask(Tutorial *tutorial, int descriptionId, int itemIds[], unsigned int itemIdsLength, bool enablePreCompletion = false);
 	virtual ~CompleteUsingItemTask();
 	virtual bool isCompleted();
-	virtual void completeUsingItem(shared_ptr<ItemInstance> item);
+	virtual void completeUsingItem(std::shared_ptr<ItemInstance> item);
 };