Added support for the /user/friends/{username} endpoint.
Added support for the /user/statuses/ endpoint.
Added support for the /user/statuses/{statusid} endpoint.
Added support for the /user/statuses/post endpoint.
Added support for the /user/watchers endpoint.
Improved all responses that use pagination.
 - Less repeated code
 - Easily extendable class RespPagination<T>