http_caldav.c: need to make sure davdb pointer in propfind ctx is NULL before each call to busytime_query_local()
http_caldav.c: skip transparents resources when doing freebusy query
http_caldav.h: FREEBUSY properties MUST use DATE-TIME, not DATE
http_caldav.c: don't allow component type or ORGANIZER to be changed on an existing resource
http_caldav: when comparing ORGANIZERs, make sure to skip "mailto:"
http_caldav.c: don't allow an attendee to reply to a non-existent invitation
http_caldav.c: don't allow ORGANIZER to be changed via overwrite
http_caldav.c: make sure we have a PARTSTAT param before trying to use it
jcal.c: "by*" rrule parts can be in array form
vzic.c, vzic-parse.c, vzic-output.c: add support for non-hierarchical TZ
aliases (e.g. GB, Cuba, Etc/*)
http_timezone.c: - allow POST to be used the same as GET
		 - for action=get the onsets should be local time in ISO format
http_timezone.c: Added tombstone at start= value for action=expand
http_timezone: use a JSON body with 404 response (now using tz_err.et for JSON error strings)
tz_err.et: update TZ_NOT_FOUND string to "tzid-not-found" per draft-douglass-timezone-service-10
http_timezone.c: consolidate TZ truncation and expansion code
http_timezone.c: added icaltime_from_year_string() for parsing 'start', 'end', 'truncate' params
http_timezone.c: suppress duplicate TZID when doing action=find
charset: add encode_mimeheader API
caldav: MIME encode generated headers

When using user-supplied data to generate message headers, it is
necessary to encode it!
http_dav.c: make sure we don't have a namespace prefix conflict when adding a namespace via ensure_ns()