feat(animate): adds basic support for CSS animations on enter and leave

Closes #3876

modules/angular2/src/animate/animation_builder.ts

@@ -0,0 +1,19 @@
+import {Injectable} from 'angular2/src/core/di';
+
+import {CssAnimationBuilder} from './css_animation_builder';
+import {BrowserDetails} from './browser_details';
+
+@Injectable()
+export class AnimationBuilder {
+  /**
+   * Used for DI
+   * @param browserDetails
+   */
+  constructor(public browserDetails: BrowserDetails) {}
+
+  /**
+   * Creates a new CSS Animation
+   * @returns {CssAnimationBuilder}
+   */
+  css(): CssAnimationBuilder { return new CssAnimationBuilder(this.browserDetails); }
+}