Final (?) change to banner, use standard unicode bullet U+25CF

This patch to the banner "hello" is hopefully the last in this new style
progress.  Previous efforts have used unicode symbols not available in
all fonts.  This time we standardize on one that looks good both the
default Ubuntu Mono and Source Code Pro fonts.  It's a bit small in my
preferred font, Envy Code R, but that might be a mistake in the font.

Not tested with PuTTY or Windows Hyper Terminal.  I think they use the
Courier font by default, both of them, which I have tested.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

src/helpers.c

@@ -146,8 +146,13 @@ void print_banner(const char *heading)
 	} else {
 		size_t wmax = 80 <= SCREEN_WIDTH ? 80 : SCREEN_WIDTH;
 
+		/* • • • Foo System ═══════════════════════════════════════════════ */
+		/* ⬤ ⬤ ⬤ Foo System ═══════════════════════════════════════════════ */
+		/* ⚉ ⚉ ⚉ Foo System ═══════════════════════════════════════════════ */
+		/* o o o Foo System ═══════════════════════════════════════════════ */
+		/* ◉ ◉ ◉ Foo System ═══════════════════════════════════════════════ */
 		/* ⦿⦿⦿ Foo System ═══════════════════════════════════════════════ */
-		strlcat(buf, "\e[1;31m⦿ \e[1;33m⦿ \e[1;32m⦿ \e[0m\e[1m ", sizeof(buf));
+		strlcat(buf, "\e[1;31m● \e[1;33m● \e[1;32m● \e[0m\e[1m ", sizeof(buf));
 		strlcat(buf, heading, sizeof(buf));
 
 		/*