Merge branch 'sl/clean-d-ignored-fix'

Merge branch 'sl/clean-d-ignored-fix'

"git clean -d" used to clean directories that has ignored files,
even though the command should not lose ignored ones without "-x".
"git status --ignored"  did not list ignored and untracked files
without "-uall".  These have been corrected.

* sl/clean-d-ignored-fix:
  clean: teach clean -d to preserve ignored paths
  dir: expose cmp_name() and check_contains()
  dir: hide untracked contents of untracked dirs
  dir: recurse into untracked dirs for ignored files
  t7061: status --ignored should search untracked dirs
  t7300: clean -d should skip dirs with ignored files