Assorted updates to "git cat-file", especially "-h".
* ab/cat-file:
cat-file: s/_/-/ in typo'd usage_msg_optf() message
cat-file: don't whitespace-pad "(...)" in SYNOPSIS and usage output
cat-file: use GET_OID_ONLY_TO_DIE in --(textconv|filters)
object-name.c: don't have GET_OID_ONLY_TO_DIE imply *_QUIETLY
cat-file: correct and improve usage information
cat-file: fix remaining usage bugs
cat-file: make --batch-all-objects a CMDMODE
cat-file: move "usage" variable to cmd_cat_file()
cat-file docs: fix SYNOPSIS and "-h" output
parse-options API: add a usage_msg_optf()
cat-file tests: test messaging on bad objects/paths
cat-file tests: test bad usage