Support remaining calendars about nodatime HOT 7 CLOSED

We're probably not going to implement the G/J cutover calendar after all: it 
has significant edge cases, and in general isn't really that useful.  See for 
example http://java.net/projects/jsr-310/lists/dev/archive/2007-05/message/121 
and the related discussion.

The Buddhist calendar is useful, but probably only worth implementing on demand.

You are doing a great work Guys, Thanks. I'm playing around with Noda Time and 
I really like it so far. About future, any plans to support Hindu calendar? For 
argument sake Buddhist calendar itself is based on Hindu calendar.

[deleted comment]

I wasn't planning on implementing a Hindu or Buddhist calendar, but I'm happy 
to look into it. Note that we're not doing any observational calendars - only 
algorithmic ones. Any specific Buddhist calendar? Is the one implemented by 
Joda Time good enough? (These days that's less of a benefit, given that the 
entire underpinnings have been refactored, but it would still be a useful 
starting point.)

Closing: too general.