Merge branch 'mh/ref-api'

Merge branch 'mh/ref-api'

* mh/ref-api:
  add_ref(): take a (struct ref_entry *) parameter
  create_ref_entry(): extract function from add_ref()
  repack_without_ref(): remove temporary
  resolve_gitlink_ref_recursive(): change to work with struct ref_cache
  Pass a (ref_cache *) to the resolve_gitlink_*() helper functions
  resolve_gitlink_ref(): improve docstring
  get_ref_dir(): change signature
  refs: change signatures of get_packed_refs() and get_loose_refs()
  is_dup_ref(): extract function from sort_ref_array()
  add_ref(): add docstring
  parse_ref_line(): add docstring
  is_refname_available(): remove the "quiet" argument
  clear_ref_array(): rename from free_ref_array()
  refs: rename parameters result -> sha1
  refs: rename "refname" variables
  struct ref_entry: document name member

Conflicts:
	cache.h
	refs.c