* Wrote utility to create an ics file (iCalendar) based on a
CalendarProvider Event. This is a good first pass, but we need
to consider whether to include alarms, etc.
* Use aforementioned utility and new convenience method to send
meeting invitations to attendees of newly created meetings (events)
when they are uploaded to the server via the CalendarSyncAdapter
* Overall, attempted to modify existing provider and rfc822 output
code as little as possible. Rfc822Output is actually very limited
in its capabilities and should be made more robust in future
Change-Id: Ie20b9137df56dc414de6737d05fa40ec9cdf47e0
18d7222359