void now() { m_time = boost::local_time::local_sec_clock::local_time(tzp.get(boost::gregorian::day_clock::local_day().year())); }
GncDateTimeImpl() : m_time(unix_epoch, tzp.get(unix_epoch.date().year())) {}
GncDateTimeImpl(PTime&& pt) : m_time(pt, tzp.get(pt.date().year())) {}
GncDateTimeImpl() : m_time(boost::local_time::local_sec_clock::local_time(tzp.get(boost::gregorian::day_clock::local_day().year()))) {}