sync: support replicating mailbox type
mboxlist.c: support CALENDAR and ADDRESSBOOK for mbtype tp/from string
user.c: user_deletedata() should also remove user's DAV DB
imapd.c: reset client inactivity timeout after cmd_syncapply() (in case it took a really long time to process)
sync_support: log mailbox updates as they occur
sync_support.c: fixed logging of mailbox updates
sync: don't parse message files while holding locks

Trying to move a large user I noticed that the global
annotations.db lock was held for ages while we did
guid checks of every single message file.  Oops!

Fixed to not do that any more.  Instead, we check
while uploading it.  We'll bail regardless, but at
least it won't be under a lock.
sync: more debug logging of "Bad protocol" events
sync: even more logging
dlist: add "dlist_splice" API (required cherry-picking dlist_getchildn())
Revert "dlist: add "dlist_splice" API (required cherry-picking dlist_getchildn())"

This reverts commit 05ffcc898c99b89c2d4ccd96d83c0c92690cafb8.

On second thought, we don't need this because the message "batching" patch
which requires this is more involvd then I want to deal with right now