[Forms] Let Angular force required rows

Pass along ng-required values such that Angular may
handle tracking of form validity based on the presence
of required fields. WTD-530.

platform/forms/res/templates/controls/select.html

@@ -1,6 +1,7 @@
 <select class='form-control input select'
         ng-model="ngModel[field]"
         ng-options="o.name for o in options"
+        ng-required="ngRequired"
         name="mctControl">
     <option value="" ng-if="!ngModel[field]">- Select One -</option>
     <span class='ui-symbol arw colorKey'>v</span>

platform/forms/res/templates/controls/textfield.html

@@ -1,6 +1,7 @@
 <span class='form-control shell'>
     <span class='field control'>
         <input type="text"
+               ng-required="ngRequired"
                ng-model="ngModel[field]"
                name="mctControl">
     </span>

platform/forms/src/MCTControl.js

@@ -50,6 +50,9 @@ define(
                     // Enabled/disabled state
                     ngDisabled: "=",
 
+                    // Whether or not input is required
+                    ngRequired: "=",
+
                     // Pattern (for input fields)
                     ngPattern: "=",