* vc-git.el: Make vc-status display information about copies,

* vc-git.el: Make vc-status display information about copies,
renames and permission changes.
(vc-git-extra-fileinfo): New defstruct.
(vc-git-escape-file-name, vc-git-file-type-as-string)
(vc-git-rename-as-string, vc-git-permissions-as-string)
(vc-git-status-printer): New functions.
(vc-git-after-dir-status-stage2): Also return vc-git-extra-fileinfo.
(vc-git-after-dir-status-stage1): Look for copies, renames and
permission changes.
(vc-git-after-dir-status-stage1-empty-db): Set permissions.
(vc-git-dir-status): Ask for staged files and renames.