v0.3.19

v0.3.19

• add format(fmt:&str) method
  format support token = ["YYYY","MM","DD","hh","mm","ss",".000000","+00:00"]

 let dt = fastdate::DateTime::from((
         fastdate::Date {
             day: 1,
             mon: 1,
            year: 2000,
         },
        fastdate::Time {
             nano: 123456000,
             sec: 11,
            minute: 1,
             hour: 1,
         })).set_offset(8 * 60 * 60);
   println!("{}",dt.format("YYYY/MM/DD/hh/mm/ss/.000000/+00:00"));
   println!("{}",dt.format("YYYY-MM-DD/hh/mm/ss"));

• add pub fn offset_hms(&self) -> (i8, i8, i8);