required variables of maker.image are not set: url, title

[jefft]

FYI, seems broken. When I try the README example with a directory containing one mp3, I get:

$ podcast --dir  . --out podcast.rss --title "Talks" --description "Podcast Description" --link http://example.com
/opt/rubies/ruby-2.1.3/lib/ruby/2.1.0/rss/maker/0.9.rb:233:in `to_feed': required variables of maker.image are not set: url, title (RSS::NotSetError)
    from /opt/rubies/ruby-2.1.3/lib/ruby/2.1.0/rss/maker/0.9.rb:48:in `setup_image'
    from /opt/rubies/ruby-2.1.3/lib/ruby/2.1.0/rss/maker/0.9.rb:33:in `to_feed'
    from /opt/rubies/ruby-2.1.3/lib/ruby/2.1.0/rss/maker/base.rb:414:in `setup_channel'
    from /opt/rubies/ruby-2.1.3/lib/ruby/2.1.0/rss/maker/0.9.rb:21:in `setup_elements'
    from /opt/rubies/ruby-2.1.3/lib/ruby/2.1.0/rss/maker/base.rb:445:in `to_feed'
    from /opt/rubies/ruby-2.1.3/lib/ruby/2.1.0/rss/maker/base.rb:439:in `make'
    from /opt/rubies/ruby-2.1.3/lib/ruby/2.1.0/rss/maker/base.rb:402:in `make'
    from /opt/rubies/ruby-2.1.3/lib/ruby/2.1.0/rss/maker.rb:28:in `make'
    from /opt/rubies/ruby-2.1.3/lib/ruby/gems/2.1.0/gems/ruby-podcast-0.0.6/lib/podcast.rb:66:in `get_rss'
    from /opt/rubies/ruby-2.1.3/lib/ruby/gems/2.1.0/gems/ruby-podcast-0.0.6/bin/podcast:72:in `<top (required)>'
    from /opt/rubies/ruby-2.1.3/bin/podcast:23:in `load'
    from /opt/rubies/ruby-2.1.3/bin/podcast:23:in `<main>'