Configure.pl: Use a Singleton

    my $singleton;
    BEGIN {
        $singleton = {
            steps   => [],
            data    => Parrot::Configure::Data->new,
            options => Parrot::Configure::Data->new,
        };
        bless $singleton, "Parrot::Configure";
    }

    sub new {
        my $class = shift;
        return $singleton;
    }

• $conf is same Parrot::Configure object in both Configure.pl and Parrot::Configure::Step