* ControlSystem is now CommandSystem for clarity and so we don't run
outta names for Systems. It's becoming time consuming to think those.
+ WeaponComponent is now GunComponent and actually does something!
+ Fixed some toString()s in various Components
+ Made up duration component, not sure this is how it should work but oh
well.
+ TimerSystem now updates DurationComponent with the time left for the
entity and flags it as Removed when it's so.
+ Created RemoveComponent to flag entities for removal 
+ Created EntityRemovalSystem. Does as its name suggests which Entities
that are tagged with a RemoveComponent.