Add remaining platform form controls; amend mct-form
and mct-control directives to better communicate state.
Begin working on problem of communicating validation
back out of the form. WTD-530.
Initial minimal working implementation where a
two-way binding between form and form user is
observable.
Notably, change ng-options to options, since
ng-options is terminal (it breaks mct-control).
WTD-530
