Use ng-show instead of ng-if to suppress the
'Select One' option after user has chosen something
in a select box; the latter appears to be incompatible
with Angular 1.4.x. nasa/openmct#113
Simplify select control's interaction with the model;
only store the value associated with the option, not
the name (which is just displayed for the user.)
WTD-530.
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.
