Odnoklassniki.ru service (with example) and Vkontakte example

Added an example for Vkontakte service.
Added new service: [Odnoklassniki.ru](http://odnoklassniki.ru).
Due to specific Odnoklassniki API-requests structure, the request() method was fully overriden and new Exception was added.
Also, an example for Odnoklassniki included