removed old period_max, period_min etc. fields and added period and epoch, which from now on will be computed from max_interval_no and min_interval_no
removed old period_max, period_min etc. fields and added period and epoch, which from now on will be computed from max_interval_no and min_interval_no


paleobiodb/pbdb-new,paleobiodb/pbdb-new,paleobiodb/pbdb-new,paleobiodb/pbdb-new,paleobiodb/pbdb-new