Solve issue #1, Accepting more arguments

[ckcksum]

Current Behavior

• terminal only accepts arguments for year and month.

New Behavior

• Accepts more arguments in the order: year, month, sun, iso, only, lang.

Changes:

Constants Added: START_FROM_SUN, WITH_ISOWEEK, ONLY_THIS_MONTH, and LANG :

• START_FROM_SUN : True if the week starts on Sunday.
  • Accepted values:
    • ["true", "t", "1", "sun", "sunday", "s", "yes", "y"]
    • ["false", "f", "0", "mon", "monday", "m", "no", "n"]
• WITH_ISOWEEK: True to display week number
  • Accepted values: ["true", "t", "1", "yes", "y"] and ["false", "f", "0", "no", "n"]
• ONLY_THIS_MONTH: Leaves days of other months as empty space without printing them.
  • Accepted values: ["true", "t", "1", "yes", "y"] and ["false", "f", "0", "no", "n"]
• LANG
  • Accepted values:
    • ["en", "english", "eng", "e"] for English
    • ["ja", "japanese", "jp", "j"] for Japanese
    • ["cht", "chinese", "cn", "c", "zh", "ch"] for Chinese.