Introduce a `dired-click-select' mode

Introduce a `dired-click-select' mode

* doc/emacs/dired.texi (Marks vs Flags): Document command bound
to `touchscreen-hold'.
* doc/lispref/commands.texi (Touchscreen Events): Describe
`touch-screen-inhibit-drag'.
* etc/NEWS: Improve description of changes to touch screen
support.
* lisp/dired-aux.el (dired-do-chxxx, dired-do-chmod)
(dired-do-print, dired-do-shell-command, dired-do-compress-to)
(dired-do-create-files, dired-do-rename, dired-do-isearch)
(dired-do-isearch-regexp, dired-do-search)
(dired-do-query-replace-regexp, dired-do-find-regexp)
(dired-vc-next-action): Disable ``click to select'' after
running this command.
* lisp/dired.el (dired-insert-set-properties): Attach
click-to-select keymap to file names if necessary.
(dired-mode-map): Bind `touchscreen-hold' to click to select
mode.
(dired-post-do-command): New function.
(dired-do-delete): Call it.
(dired-mark-for-click, dired-enable-click-to-select-mode): New
functions.
(dired-click-to-select-mode): New minor mode.
* lisp/touch-screen.el (touch-screen-current-tool): Fix doc
string.
(touch-screen-inhibit-drag): New function.