fix mordad word and fix test

[abujafari]

[arashm]

Hi. Thanks for the pull request and sorry for the very very long response. This is not a mistake and I wrote it like that by choice. "امرداد" is the more correct term for the month name, you can see this or search for "مرداد یا امرداد" in google. I'm not sure if I want to change it. A better way may be to make the month/days names configurable by user. Unfortunately I haven't had much time to put on this project, but I guess I'll be able to update it this weekend hopefully.