We currently use an int to tell us whether --batch parsing
is on, and if so, whether we should print the full object
contents. Let's instead factor this into a struct, filled in
by callback, which will make further batch-related options
easy to add.
Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>