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/SlimeModel.cpp

@@ -34,7 +34,7 @@ SlimeModel::SlimeModel(int vOffs)
 	cube->compile(1.0f/16.0f);
 }
 
-void SlimeModel::render(shared_ptr<Entity> entity, float time, float r, float bob, float yRot, float xRot, float scale, bool usecompiled)
+void SlimeModel::render(std::shared_ptr<Entity> entity, float time, float r, float bob, float yRot, float xRot, float scale, bool usecompiled)
 {
     setupAnim(time, r, bob, yRot, xRot, scale);