XHR and dependency injection

 * Replaced the in-memory dataset with data loaded from the server (in
   the form of static phone.json file)
   - The json file is loaded using the $http service
 * Demonstrate the use of services and dependency injection
XHR and dependency injection

 * Replaced the in-memory dataset with data loaded from the server (in
   the form of static phone.json file)
   - The json file is loaded using the $http service
 * Demonstrate the use of services and dependency injection