static register( component ) {

		if ( !this.elements.includes( component ) ) {

				this.elements.push( component );

		}

	}
Job:
- recording components required updates
- trigger those updates when 'update' is called

This module is a bit special. It is, with FontLibrary, one of the only modules in the 'component'
directory not to be used in component composition (Object.assign).

When MeshUIComponent is instanciated, it calls UpdateManager.register().

Then when MeshUIComponent receives new attributes, it doesn't update the component right away.
Instead, it calls UpdateManager.requestUpdate(), so that the component is updated when the user
decides it (usually in the render loop).

This is best for performance, because when a UI is created, thousands of componants can
potentially be instantiated. If they called updates function on their ancestors right away,
a given component could be updated thousands of times in one frame, which is very ineficient.

Instead, redundant update request are moot, the component will update once when the use calls
update() in their render loop.