- opensync plugin:

- opensync plugin:
       - fixed ID mapping bug in the case of a non-numeric UID
	       from syncing external -> Barry, and then the
	       new Barry ID would look like a new change
	       when syncing back from Barry -> external.
       - added support for slow sync
       - added clear() to idmap class
       - added vformat attr parameter extraction class
       - added more trace logging during vformat/Barry conversions
       - added Notification time support
       - handled "all day" vformat special case, when DTEND
	       does not exist in a vformat data block
- changed the min1900_t time conversion functions to handle
       the 0xffffffff special case, when notifications
       are turned off on a calendar event (src/time.cc)
- also made the calendar data dump output clearer for
       disabled timestamps, and added debug output
       for the raw min1900 value, in case there are more
       special cases in the future