- Cursors now have "arraysize" set to 50 by default on

- Cursors now have "arraysize" set to 50 by default on
them, the value of which is configurable using the
"arraysize" argument to create_engine() with the
Oracle dialect.  This to account for cx_oracle's default
setting of "1", which has the effect of many round trips
being sent to Oracle.  This actually works well in
conjunction with BLOB/CLOB-bound cursors, of which
there are any number available but only for the life of
that row request (so BufferedColumnRow is still needed,
but less so). [ticket:1062]