rtorrent: added assert about empty custom keys
rtfetch: fixed disabled --save-customs
rtload: don't raise error if data directory already exists; refactor
Separate tools.fs.treeList()
tools.cli.progress() -> tools.fmt.formatProgress()
rtfetch: fixed unknown counter #2
clientlib: Common exception NoSuchTorrentError() for uniform plugins interface
rtorrent: transform xmlrpclib.Fault() with code -501 to clientlib.NoSuchTorrentError()
rtorrent.Client.files(): using the multicast
tools.fs.treeListToDict(): convert plain files list to dict
rtfile: scripting options: extract meta fields by options, pretty tree formatting