New: OPTION_DROP_SEQUENCE

Controls the behavior of query bracktes with zero based integer sequences.

    $url->setQueryVariables(array('foo' => array('bar', 'baz')));

    TRUE (default): http://example.org/?foo[]=bar&foo[]=baz
    FALSE         : http://example.org/?foo[0]=bar&foo[1]=baz

The now default behavior was previously not possible.

If the former default behavior is needed to be retained, the
OPTION_DROP_SEQUENCE needs to be set to boolean false.