(vc-client-object): Remove.

(vc-client-object): Remove.
(vc-dir-prepare-status-buffer): Take a backend as an argument and
use it when looking for a buffer.
(vc-dir): Add a backend argument.  Set revert-buffer-function.
Don't create a client object.  Move bindings ...
(vc-dir-menu-map, vc-dir-mode-map): ... here.
(vc-dir-revert-buffer-function): New function.
(vc-generic-status-printer): Rename to ...
(vc-dir-status-printer): ... this.
(vc-generic-state, vc-generic-status-fileinfo-extra)
(vc-dir-extra-menu, vc-make-backend-object): Remove.
(vc-default-status-printer): Use a different face for
directories.  Don't display any text for directories in the state
column.  Add tooltips.