* subr.el (listify-key-sequence-1): Use normal syntax since those

* subr.el (listify-key-sequence-1): Use normal syntax since those
integers are nowadays always represented by the same (positive) number
on all platforms.
(read-key-empty-map): New const.
(read-key-delay): New var.
(read-key): New function.
(force-mode-line-update): Use with-current-buffer.
(locate-user-emacs-file): Don't forget to abbreviate the file name.
(start-process-shell-command, start-file-process-shell-command):
Discourage the use of command-args.

* processes.texi (Asynchronous Processes): Adjust arglist of
start-process-shell-command and start-file-process-shell-command.