Changelog:
- Add Lifetimer and remove hurtbox on hit
- Still insta-remove on player hit
- Fix adding a component to an entity that already has that component
- Reorder lifetimer update system
Changelog:
- Add function spawn arrow
- Update game system to handle null components
- enough for the arrow to work
- Render arrow, sort of
- Initial implementation, definitely need more work
Since an entity is essentially tied to a manager, put it as a field in
Entity. This means no need to pass entity manager when getting a
component, which is more intuitive.