Merge branch 'jk/no-funny-object-types'

Support to create a loose object file with unknown object type has
been dropped.

* jk/no-funny-object-types:
  object-file: drop support for writing objects with unknown types
  hash-object: handle --literally with OPT_NEGBIT
  hash-object: merge HASH_* and INDEX_* flags
  hash-object: stop allowing unknown types
  t: add lib-loose.sh
  t/helper: add zlib test-tool
  oid_object_info(): drop type_name strbuf
  fsck: stop using object_info->type_name strbuf
  oid_object_info_convert(): stop using string for object type
  cat-file: use type enum instead of buffer for -t option
  object-file: drop OBJECT_INFO_ALLOW_UNKNOWN_TYPE flag
  cat-file: make --allow-unknown-type a noop
  object-file.h: fix typo in variable declaration

diff --cc Makefile
Simple merge

diff --cc object-store.c
Simple merge

diff --cc object-store.h
Simple merge