feat(ngAnimate): complete rewrite of animations

- ngAnimate directive is gone and was replaced with class based animations/transitions
- support for triggering animations on css class additions and removals
- done callback was added to all animation apis
- $animation and $animator where merged into a single $animate service with api:
  - $animate.enter(element, parent, after, done);
  - $animate.leave(element, done);
  - $animate.move(element, parent, after, done);
  - $animate.addClass(element, className, done);
  - $animate.removeClass(element, className, done);

BREAKING CHANGE: too many things changed, we'll write up a separate doc with migration instructions

css/angular.css

@@ -8,3 +8,7 @@
 ng\:form {
   display: block;
 }
+
+.ng-hide {
+  display: none;
+}