Refactor screen_init(), use methods developed in pimd project

- Refactor screen_init()
  - use native impl. of TTY probing from pimd project
    - check if TIOCWINSZ works
    - check if we're running in watch(1), for initctl
  - check if ANSI goto(999,999) escape seq. works (invasive)
  - fallback to 80x24
- Drop screen_exit()
- Rename screen_init() to get_width(), for now, matching pimd
- Relocate call in main() to banner(), first fn to write to TTY

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

src/finit.c

@@ -478,10 +478,6 @@ int main(int argc, char *argv[])
 	chdir("/");
 	umask(0);
 
-	/* Set up canvas */
-	if (!rescue && !debug)
-		screen_init();
-
 	/* Allow progress, if enabled */
 	enable_progress(1);
 
@@ -490,8 +486,10 @@ int main(int argc, char *argv[])
 	 */
 	emergency_shell();
 
-	/* Load plugins early, the first hook is in banner(), so we
-	 * need plugins loaded before calling it. */
+	/*
+	 * Load plugins early, the first hook is in banner(), so we
+	 * need plugins loaded before calling it.
+	 */
 	plugin_init(&loop);
 
 	/*