This entails adding callbacks to dartdoc for injecting additional
comments, as well as adding somewhat deeper support for hashing and
equality testing of Frog objects.
The next step is to inject the annotations into the HTML and DOM library source itself.
Review URL: http://codereview.chromium.org//8771054
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@2199 260f80e4-7a28-3924-810f-c04153c831b5
