CalendarConversions: now with the Jalali calendar

I fear we have lost @ehsan as a direct contributor, but I would still like his code to make it in to production.  In particular, this calendar conversions work should be on the site.

@mintsoft The date_output_format doesn't work so well here because the month names (I expect) are different.  How do you feel about this ISO-8601 (with time elided) version?