#1 Allow unspecified author names

[Anders Thulin]

I see that <author> must contain <familyname>, followed
by an optional <givenname>. This works well when the
name of the author is know, or the exact author name
isn't important to preserve.

But it doesn't work for tourney problems for which the
author identity hasn't been revealed yet. For these,
the motto is the most appropriate author
identification, yet it cannot be asserted that it is
any kind of family name.

Another case is that of unfamiliar languages: I may
have a problem with the (to me) unknown author of
'RICZU LAJOS'.
I can't decide which part is the family name (or
perhaps even if both parts are, such as for some
south-american problemists), and I may prefer to avoid
asserting that either is, to avoid database rot
(records end up with wrong keys, and so become
difficult to find).

Suggestion: allow also familyname to be optional.

This would permit <author>RICZU LAJOS</author>, and
so allow the decision to be postponed.

Alternatively, if <familyname> is not what it seems to
be -- i.e. an assertion that that text is indeed a
family name, and should be allowed to be treated as
such -- it may be an idea to document such semantic
oddities somewhere.