Fixes issue with multiple authors

[chdorner]

If an OPDS entry file has multiple authors, it returns:

[
  {:name=>"Randall Garrett", :uri=>"http://www.feedbooks.com/author/267", :email=>nil},
  {:name=>"Randall Garrett", :uri=>"http://www.feedbooks.com/author/267", :email=>nil}
]

It now works as expected and returns:

[
  {:name=>"Randall Garrett", :uri=>"http://www.feedbooks.com/author/267", :email=>nil},
  {:name=>"Stephen Marlowe", :uri=>"http://www.feedbooks.com/author/744", :email=>nil}
]

[zetaben]

Thanks for the fix