[OM - 553]CalDAV support

[Ankush Mishra]

Well, I've been looking here and there of the OM code and the rest such 
as libraries and so forth, and here's what I have come up with. After 
analyzing the libraries, and having decided on one. One clarification 
I'd like to ask is that, since we don't seem to have recurrence events 
support, should we/I implement that as well?

Ankush Mishra