sb/more-repo-in-api, was Re: What's cooking in git.git (Jan 2019, #01; Mon, 7)

> * sb/more-repo-in-api (2018-12-28) 23 commits
>  - t/helper/test-repository: celebrate independence from the_repository
>  - path.h: make REPO_GIT_PATH_FUNC repository agnostic
>  - commit: prepare free_commit_buffer and release_commit_memory for any repo
>  - commit-graph: convert remaining functions to handle any repo
>  - submodule: don't add submodule as odb for push
>  - submodule: use submodule repos for object lookup
>  - pretty: prepare format_commit_message to handle arbitrary repositories
>  - commit: prepare logmsg_reencode to handle arbitrary repositories
>  - commit: prepare repo_unuse_commit_buffer to handle any repo
>  - commit: prepare get_commit_buffer to handle any repo
>  - commit-reach: prepare in_merge_bases[_many] to handle any repo
>  - commit-reach: prepare get_merge_bases to handle any repo
>  - commit-reach.c: allow get_merge_bases_many_0 to handle any repo
>  - commit-reach.c: allow remove_redundant to handle any repo
>  - commit-reach.c: allow merge_bases_many to handle any repo
>  - commit-reach.c: allow paint_down_to_common to handle any repo
>  - commit: allow parse_commit* to handle any repo
>  - object: parse_object to honor its repository argument
>  - object-store: prepare has_{sha1, object}_file to handle any repo
>  - object-store: prepare read_object_file to deal with any repo
>  - object-store: allow read_object_file_extended to read from any repo
>  - packfile: allow has_packed_and_bad to handle arbitrary repositories
>  - sha1_file: allow read_object to read objects in arbitrary repositories
>  (this branch is used by jt/get-reference-with-commit-graph and md/list-objects-filter-by-depth.)
> 
>  The in-core repository instances are passed through more codepaths.