docs($animate): detail options object

- Document options object used in various $animate methods

Author: wesleycho

src/ng/animate.js

@@ -420,7 +420,14 @@ var $AnimateProvider = ['$provide', function($provide) {
        * @param {DOMElement} parent the parent element which will append the element as
        *   a child (so long as the after element is not present)
        * @param {DOMElement=} after the sibling element after which the element will be appended
-       * @param {object=} options an optional collection of options/styles that will be applied to the element
+       * @param {object=} options an optional collection of options/styles that will be applied to the element.
+       *   The object has the following properties:
+       *
+       *   - **addClass** - `{string}` - space-separated CSS classes to add to element
+       *   - **from** - `{Object}` - CSS properties & values from beginning of animation
+       *   - **removeClass** - `{string}` - space-separated CSS classes to remove from element
+       *   - **to** - `{Object}` - CSS properties & values at end of animation
+       *
        *
        * @return {Promise} the animation callback promise
        */