- Query.count() has been enhanced to do the "right

- Query.count() has been enhanced to do the "right
thing" in a wider variety of cases. It can now
count multiple-entity queries, as well as
column-based queries. Note that this means if you
say query(A, B).count() without any joining
criterion, it's going to count the cartesian
product of A*B. Any query which is against
column-based entities will automatically issue
"SELECT count(1) FROM (SELECT...)" so that the
real rowcount is returned, meaning a query such as
query(func.count(A.name)).count() will return a value of
one, since that query would return one row.