- query.one() no longer applies LIMIT to the query, this to

- query.one() no longer applies LIMIT to the query, this to
ensure that it fully counts all object identities present
in the result, even in the case where joins may conceal
multiple identities for two or more rows.  As a bonus,
one() can now also be called with a query that issued
from_statement() to start with since it no longer modifies
the query.  [ticket:1688]