Merge branch 'zh/ref-filter-raw-data'

Prepare the "ref-filter" machinery that drives the "--format" option of "git for-each-ref" and its friends to be used in "git cat-file --batch". * zh/ref-filter-raw-data: ref-filter: add %(rest) atom ref-filter: use non-const ref_format in *_atom_parser() ref-filter: --format=%(raw) support --perl ref-filter: add %(raw) atom ref-filter: add obj-type check in grab contents