Add support for Dari and Pashto

[mikedawson]

Hi,

This library has been great! As Afghanistan is also using the Persian calendar, we wanted to add Dari and Pashto. My colleague @varunasingh have worked on this. We added minor changes so that it uses resource string xml instead of constants. We have then added Farsi, Dari, and Pashto string xml files.

We hope this can be added to the main repository here so others can make use of it.

Thanks!

[aliab]

Thank you for your contribution, it will be available in the next version.