Return value
array - a two dimensional, nested array
indicated by the name of the newsgroup, every entry contains
information about the newsgroup:
$groups[newsgroup_name]['group']
Name of the newsgroup
$groups[newsgroup_name]['last']
Number of the last article
$groups[newsgroup_name]['first']
Number of the first article
$groups[newsgroup_name]['posting']
values: y - yes,
n - no,
m - moderated)