Add ng-required to radio group

Author: kentongray

src/directives/formly-field-radio.html

@@ -10,6 +10,7 @@
 				   name="{{id}}"
 				   id="{{id + '_'+ $index}}"
 				   ng-value="option.value"
+                   ng-required="options.required"
 				   ng-model="$parent.value">
 			{{option.name}}
 		</label>