Odnoklassniki.ru service (with example) and Vkontakte example

Added an example for Vkontakte service.
Added new service: Odnoklassniki.ru.
Due to specific Odnoklassniki API-requests structure, the request() method was fully overriden, new Exception was added and two additional methods added: setApplicationKey($key) and getApplicationKey() (needed for API requests)
Also, an example for Odnoklassniki included (see it for details).