Updates of the time-format fixing problem
** be aware that this update is based on integer fixing update
The following are the fixing:
In neptuneClass.f90

1. use "date2longstring" function (It's a function! Not a subroutine! So don't use call function but directly use it!)
2. update all of the format function

regarding format epoch_string length: Theoretically a value for epoch_string should be set as 27 (according to LEN_TIME_STRING_LONG). But as it's a changing variable it's set as empty to import it from the length of epoch_string itself