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']
message number of the last message
$groups[newsgroup_name]['first']
message number of the first message
$groups[newsgroup_name]['posting_allowed']
values: y - yes,
n - no,
m - moderated)
$groups[newsgroup_name]['desc']
newsgroup description