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/SnowManRenderer.h

@@ -13,5 +13,5 @@ public:
 	SnowManRenderer();
 
 protected:
-	virtual void additionalRendering(shared_ptr<Mob> _mob, float a);
+	virtual void additionalRendering(std::shared_ptr<Mob> _mob, float a);
 };