Overall cleanup of the Library: (1) Making sure we use static strings instead of inline string, (2) Making sure that we use the Mixins when available and not duplicate code, (3) Making sure variables are final on setters, (4) Making sure that elements have the appropriate attributes
Adding in some missed HandlerRegistration's for handlers.
Adding in the EnabledMixin/HasEnabled and adding it to the ValueBoxBase.
Adding in MaxLength attribute to the ValueBoxBase.