Fix bug#13708

* lisp/icomplete.el (icomplete-minibuffer-map): Unbind `C-s' and `C-r'.
Bind `C-.' and `C-,' to `icomplete-forward-completions' and
`icomplete-backward-completions'.

* lisp/ido.el (ido-init-completion-maps): Bind `C-.' and `C-,' to
`ido-next-match' and `ido-prev-match' resply.

* lisp/iswitchb.el (iswitchb-read-buffer): Bind `C-.' and `C-,' to
`iswitchb-next-match' and `iswitchb-prev-match' resply.
Use locate-user-emacs-file. * lisp/type-break.el (type-break-file-name): * lisp/textmodes/remember.el (remember-data-file): * lisp/strokes.el (strokes-file): * lisp/shadowfile.el (shadow-initialize): * lisp/saveplace.el (save-place-file): * lisp/ps-bdf.el (bdf-cache-file): * lisp/progmodes/idlwave.el (idlwave-config-directory): * lisp/net/quickurl.el (quickurl-url-file): * lisp/international/kkc.el (kkc-init-file-name): * lisp/ido.el (ido-save-directory-list-file): * lisp/emulation/viper.el (viper-custom-file-name): * lisp/emulation/vip.el (vip-startup-file): * lisp/calendar/todo-mode.el (todo-file-do, todo-file-done, todo-file-top): * lisp/calendar/timeclock.el (timeclock-file): Use locate-user-emacs-file.