Prepare release `0.3.0`

Changelog:
* [BC break] `AccountConnectorInterface::connect()` method now requires the first
  parameter to be instance of `Symfony\Component\Security\Core\User\UserInterface`
* [BC break] `ConnectController::authenticateUser()` method now requires the first
  parameter to be instance of `Symfony\Component\HttpFoundation\Request`
* [BC break] Removed `AbstractResourceOwner::addOptions()` method
* [BC break] `OAuthUtils::getAuthorizationUrl()` & `OAuthUtils::getLoginUrl()` methods
  now expect first parameter to be instance of `Symfony\Component\HttpFoundation\Request`
* [BC break] LinkedIn resource owner now uses OAuth2 approach, visit official
  web page for details how to migrate: https://developer.linkedin.com/documents/authentication#migration
* [BC break] Dropbox resource owner now uses OAuth2 approach
* Added ability to merge response parts into single path
* Added Bitly resource owner
* Added Box resource owner
* Added Dailymotion resource owner
* Added DeviantArt resource owner
* Added Eventbrite resource owner
* Added Mail.ru resource owner
* Added Sina Weibo resource owner
* Added QQ.com resource owner
* Added Trello resource owner
* Added Wordpress resource owner