News::Newsrc manages newsrc files, of the style

    alt.foo: 1-21,28,31-34
    alt.bar! 3,5,9-2900,2902

Methods are provided for

    * reading and writing newsrc files
    * adding and removing newsgroups
    * changing the order of newsgroups
    * subscribing and unsubscribing from newsgroups
    * testing whether groups exist and are subscribed
    * marking and unmarking articles
    * testing whether articles are marked
    * returning lists of newsgroups
    * returning lists of articles
