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/BossMobPart.cpp

@@ -37,7 +37,7 @@ bool BossMobPart::hurt(DamageSource *source, int damage)
 	return bossMob->hurt( dynamic_pointer_cast<BossMobPart>( shared_from_this() ), source, damage);
 }
 
-bool BossMobPart::is(shared_ptr<Entity> other)
+bool BossMobPart::is(std::shared_ptr<Entity> other)
 {
 	return shared_from_this() == other || bossMob == other.get();
 }