zipangu 0.2.0

• Added several functions to handle postal code data.
  • read_zipcode() to read Japan post's zip-code file and dl_zipcode_file() for raw file download.
  • is_zipcode() test zip-code. Only supports 7-digit numbers or characters.
  • zipcode_spacer() insert and remove zip-code connect character.
• str_jconv() and str_conv_*() converts the kind of string used as Japanese people.
• Added some functions related to Japanese holidays.
  • jholiday_spec() to find date from corresponding year and holiday name and jholiday() is used to look up a list of holidays for the year.
  • is_jholiday() whether the day is a holiday.
• Find out the date of the specific month and weekday (find_date_by_wday())