Fix ediff problems. (Reported by Dan Nicolaescu.)

Fix ediff problems.  (Reported by Dan Nicolaescu.)

* lisp/subr.el (with-selected-frame): Make sure the current buffer is
  restored as well.

* src/xfns.c (Fx_create_frame): Use `store_frame_param' to set
  `window-system' frame parameter, and make sure it overrides any
  user-supplied setting.

* src/xfns.c (x_icon): Disable redundant call to
  `x_wm_set_window_state'. (Also applied in CVS.)

* lisp/faces.el (x-create-frame-with-faces): Don't make frame visible
  until we are done setting up all its parameters.

* lisp/ediff-wind.el (ediff-setup-windows-automatic): New function.
  (ediff-window-setup-function): Use it as default.

git-archimport-id: lorentey@elte.hu--2004/emacs--multi-tty--0--patch-528