Bug 1095355 - Create KeyView component.

It looks like I (or we) are making a wrong assumption about the relation between view manager and the views. A view like `AlternativesCharMenuView` should be able to register multiple `targetObject -> view` mapping since itself is responsible of creating multiple `KeyView`s.

Let's discuss this in person and come up with proper API on this (other than exposing the `viewMap`).