Air Explorer 2.1.1., new version

List of changes: -Two factor auth support for Mail.ru -Added hash synchronization support for Dropbox. -Fixed max 500 items in Mail.ru folders. -Hash synchronization option was not displayed correctly for saved tasks. -Filter and custom synchronization options were not displayed correctly for saved tasks. -Show the Air Explorer version in the logs. -Reduced the chances of getting max requests limit on Box. -Fixed uploading files to Mediafire. -Fixed saving synchronizations with accounts with the same name for the same cloud but different alias.