Merge branch 'js/read-tree' into js/c-merge-recursive

Merge branch 'js/read-tree' into js/c-merge-recursive

* js/read-tree: (107 commits)
  read-tree: move merge functions to the library
  read-trees: refactor the unpack_trees() part
  tar-tree: illustrate an obscure feature better
  git.c: allow alias expansion without a git directory
  setup_git_directory_gently: do not barf when GIT_DIR is given.
  Build on Debian GNU/kFreeBSD
  Call setup_git_directory() much earlier
  Call setup_git_directory() early
  Display an error from update-ref if target ref name is invalid.
  Fix http-fetch
  t4103: fix binary patch application test.
  git-apply -R: binary patches are irreversible for now.
  Teach git-apply about '-R'
  Makefile: ssh-pull.o depends on ssh-fetch.c
  log and diff family: honor config even from subdirectories
  git-reset: detect update-ref error and report it.
  lost-found: use fsck-objects --full
  Teach git-http-fetch the --stdin switch
  Teach git-local-fetch the --stdin switch
  Make pull() support fetching multiple targets at once
  ...