Merge branch 'th/diff'

Merge branch 'th/diff'

* th/diff:
  builtin-diff: turn recursive on when defaulting to --patch format.
  t4013: note improvements brought by the new output code.
  t4013: add format-patch tests.
  format-patch: fix diff format option implementation
  combine-diff.c: type sanity.
  t4013 test updates for new output code.
  Fix some more diff options changes.
  Fix diff-tree -s
  log --raw: Don't descend into subdirectories by default
  diff-tree: Use ---\n as a message separator
  Print empty line between raw, stat, summary and patch
  t4013: add more tests around -c and --cc
  whatchanged: Default to DIFF_FORMAT_RAW
  Don't xcalloc() struct diffstat_t
  Add msg_sep to diff_options
  DIFF_FORMAT_RAW is not default anymore
  Set default diff output format after parsing command line
  Make --raw option available for all diff commands
  Merge with_raw, with_stat and summary variables to output_format
  t4013: add tests for diff/log family output options.