Update README.md

Added:
* [**$touched is the new $dirty – AngularJS Migration Guide 1.2 to 1.3] (http://blog.lingohub.com/developers/2014/10/angularjs-migration-guide-1-2-to-1-3/)
* Added link to Google's blog post announcing 1.3.0
* Added a link to Google's 1.2 to 1.3 migration guide
* [**Exploring Angular 1.3 - One-Time Bindings] (http://blog.thoughtram.io/angularjs/2014/10/14/exploring-angular-1.3-one-time-bindings.html)
* [**Exploring Angular 1.3 - ng-model-options] (http://blog.thoughtram.io/angularjs/2014/10/19/exploring-angular-1.3-ng-model-options.html)
* [**Exploring Angular 1.3 - Stateful Filters] (http://blog.thoughtram.io/angularjs/2014/11/19/exploring-angular-1.3-stateful-filters.html)