Merge branch 'pw/p4-update'

* pw/p4-update:
  git-p4: handle files with shell metacharacters
  git-p4: keyword flattening fixes
  git-p4: stop ignoring apple filetype
  git-p4: recognize all p4 filetypes
  git-p4: handle utf16 filetype properly
  git-p4 tests: refactor and cleanup

Author: gitster