Updated rtorrent-python library

 - Fixed bug with basic auth on secure connections
 - Added 'test_connection' method to RTorrent class
 - Minor adjustment to authorization encoding
[rtorrent] cleaned up connection, '+https' is now added to 'httprpc' protocol if SSL option is enabled
Removed print statement from rtorrent downloader
Merge pull request #3000 from fuzeman/feature/dev_rtorrent

[rtorrent] Fixed connection bug when using SSL + Basic Auth