Fix it wraps multiply when imported more than once
Add hack to make debug output for object readable

The dump of a Time::Piece object is looks like

    bless( [
             0,
             0,
             0,
             1,
             0,
             '70',
             4,
             0,
             0,
             0,
             1
           ], 'Time::Piece' );

It is unreadable. This hack makes it readable as

    bless( do{\(my $o = '1970-01-01T00:00:00')}, 'Time::Piece#stringify' )