feat(formly-form): Expand formly-form restriction to be both Element and Attribute

Formly-form was previously restricted as only an HTML element. Although that is still the
recommended usage, it is now allowed to also be used as an attribute.

closes #450

Author: CrockAgile

src/directives/formly-form.js

@@ -5,13 +5,13 @@ export default formlyForm;
 /**
  * @ngdoc directive
  * @name formlyForm
- * @restrict E
+ * @restrict AE
  */
 // @ngInject
 function formlyForm(formlyUsability, formlyWarn, $parse, formlyConfig, $interpolate) {
   let currentFormId = 1;
   return {
-    restrict: 'E',
+    restrict: 'AE',
     template: formlyFormGetTemplate,
     replace: true,
     transclude: true,

src/directives/formly-form.test.js

@@ -21,7 +21,7 @@ describe('formly-form', () => {
     scope.fields = [];
   }));
 
-  it.skip(`should be possible to use it as an attribute directive`, () => {
+  it(`should be possible to use it as an attribute directive`, () => {
     const el = compileAndDigest(`
       <div formly-form model="model" fields="fields" form="theForm"></formly-form>
     `);