feat(Animate): add support for maybe correct ng1 css animation classes

 - roughly approximate by adding {name}-add {name}-add-active {name}-remove {name}-remove-active classes during animation.
 - I'm not 100% sure this is correct, but it did work for the sidenav animation. Because the animation stuff is just placeholder waiting for official animation support, this is good enough for me.

ng2-material/core/util/animate.ts

@@ -1,4 +1,5 @@
 import {DOM} from 'angular2/src/platform/dom/dom_adapter';
+import {TimerWrapper} from "angular2/src/facade/async";
 
 /**
  * Provide an API for animating elements with CSS transitions
@@ -13,30 +14,42 @@ export class Animate {
   static enter(el: HTMLElement, cssClass: string): Promise<void> {
     DOM.removeClass(el, cssClass);
     return new Promise<void>((resolve)=> {
-      var duration = Animate.getTransitionDuration(el, true);
-      var callTimeout = setTimeout(() => done(), duration);
-      var done = () => {
-        clearTimeout(callTimeout);
-        removeListener();
-        resolve();
-      };
-      let removeListener = DOM.onAndCancel(el, Animate.TRANSITION_EVENT, done);
-      DOM.addClass(el, cssClass);
+      DOM.addClass(el, cssClass + '-add');
+      TimerWrapper.setTimeout(() => {
+        var duration = Animate.getTransitionDuration(el, true);
+        var callTimeout = setTimeout(() => done(), duration);
+        var done = () => {
+          DOM.removeClass(el, cssClass + '-add-active');
+          DOM.removeClass(el, cssClass + '-add');
+          clearTimeout(callTimeout);
+          removeListener();
+          resolve();
+        };
+        let removeListener = DOM.onAndCancel(el, Animate.TRANSITION_EVENT, done);
+        DOM.addClass(el, cssClass + '-add-active');
+        DOM.addClass(el, cssClass);
+      }, 1);
     });
   }
 
   static leave(el: HTMLElement, cssClass: string): Promise<void> {
     return new Promise<void>((resolve)=> {
-      var duration = Animate.getTransitionDuration(el, true);
-      var callTimeout = setTimeout(() => done(), duration);
+      DOM.addClass(el, cssClass + '-remove');
+      TimerWrapper.setTimeout(() => {
+        var duration = Animate.getTransitionDuration(el, true);
+        var callTimeout = setTimeout(() => done(), duration);
 
-      var done = () => {
-        clearTimeout(callTimeout);
-        removeListener();
-        resolve();
-      };
-      let removeListener = DOM.onAndCancel(el, Animate.TRANSITION_EVENT, done);
-      DOM.removeClass(el, cssClass);
+        var done = () => {
+          DOM.removeClass(el, cssClass + '-remove-active');
+          DOM.removeClass(el, cssClass + '-remove');
+          clearTimeout(callTimeout);
+          removeListener();
+          resolve();
+        };
+        let removeListener = DOM.onAndCancel(el, Animate.TRANSITION_EVENT, done);
+        DOM.addClass(el, cssClass + '-remove-active');
+        DOM.removeClass(el, cssClass);
+      }, 1);
     });
   }