added ability to set default for select element

Author: ghelton

src/directives/formly-field-select.html

@@ -8,6 +8,7 @@
 			ng-model="value"
 			ng-required="options.required"
 			ng-disabled="options.disabled"
+			ng-init="value = options.options[options.default]"
 			ng-options="option.name group by option.group for option in options.options">
 	</select>
 </div>