(command-line): Rename `inhibit-startup-message' to

(command-line): Rename `inhibit-startup-message' to
`inhibit-startup-screen'.
(fancy-about-text): Use shorter label for "Ordering Manuals".
(fancy-startup-tail): Add optional arg `concise'.  When `concise'
is nil, display a line with "To start..." and 3 links to useful
tasks.  Display the "Dismiss" button and "Don't show this message
again" only when concise is non-nil.
(fancy-startup-screen): Call `fancy-startup-tail' with optional
arg `concise'.  If CONCISE is non-nil, display a concise version
of the splash screen in another window.  Otherwise, switch to the
startup buffer in the same window.
(startup-echo-area-message): Change displayed binding from
C-h C-p (describe-project) to C-h C-a (about-emacs), and change
text "about the GNU system and GNU/Linux" to "about GNU Emacs and
the GNU system".
(display-startup-screen): Fix buffer name from "*About GNU Emacs*"
to "*GNU Emacs*".
(display-about-screen): Don't check the existence of the buffer
"*About GNU Emacs*".
(display-splash-screen): Make alias to `display-startup-screen'.
(command-line-1): Rename `inhibit-startup-message' to
`inhibit-startup-screen'.  Inhibit startup screen when Emacs is
started with command line options "-f", "-funcall", "-e", "-eval",
"-execute", "-insert", "-find-file", "-file", "-visit".
Inhibit startup screen when Emacs is started with a file name only
on tty (i.e. don't inhibit it when started with a file name like
"emacs FILE..." on a window system).
(command-line-1): Simplify logic of displaying the startup screen:
if file-count > 0, then display the concise version in another
window, otherwise display full version in the same window.