Conversion from unsigned char [40] to struct object_id continues.

* bc/object-id:
  Documentation: update and rename api-sha1-array.txt
  Rename sha1_array to oid_array
  Convert sha1_array_for_each_unique and for_each_abbrev to object_id
  Convert sha1_array_lookup to take struct object_id
  Convert remaining callers of sha1_array_lookup to object_id
  Make sha1_array_append take a struct object_id *
  sha1-array: convert internal storage for struct sha1_array to object_id
  builtin/pull: convert to struct object_id
  submodule: convert check_for_new_submodule_commits to object_id
  sha1_name: convert disambiguate_hint_fn to take object_id
  sha1_name: convert struct disambiguate_state to object_id
  test-sha1-array: convert most code to struct object_id
  parse-options-cb: convert sha1_array_append caller to struct object_id
  fsck: convert init_skiplist to struct object_id
  builtin/receive-pack: convert portions to struct object_id
  builtin/pull: convert portions to struct object_id
  builtin/diff: convert to struct object_id
  Convert GIT_SHA1_RAWSZ used for allocation to GIT_MAX_RAWSZ
  Convert GIT_SHA1_HEXSZ used for allocation to GIT_MAX_HEXSZ
  Define new hash-size constants for allocating memory