refactor(LifecycleEvent): remove LifecycleEvent

fixes #3924

BREAKING CHANGE

The `lifecycle` configuration for directive has been dropped.

Before

    // Dart
    @Component({lifecycle: const [LifecycleEvent.OnChanges], ...})
    class MyComponent implements OnChanges {
      void onChanges() {...}
    }

    // Typescript
    @Component({lifecycle: [LifecycleEvent.OnChanges], ...})
    class MyComponent implements OnChanges {
      onChanges(): void {...}
    }

    // ES5
    var MyComponent = ng.
    Component({lifecycle: [LifecycleEvent.OnChanges], ...}).
    Class({
      onChanges: function() {...}
    });

After

    // Dart
    @Component({...})
    class MyComponent implements OnChanges {
      void onChanges() {...}
    }

    // Typescript
    @Component({...})
    class MyComponent implements OnChanges {
      onChanges(): void {...}
    }

    // ES5
    var MyComponent = ng
      .Component({...})
      .Class({
        onChanges: function() {
        }
      });

modules/examples/e2e_test/model_driven_forms/model_driven_forms_spec.ts

@@ -1,6 +1,6 @@
 import {verifyNoBrowserErrors} from 'angular2/src/test_lib/e2e_util';
 
-describe('Template-Driven Forms', function() {
+describe('Model-Driven Forms', function() {
 
   afterEach(verifyNoBrowserErrors);