Pause the execution (10s max) if any errors are displayed so the user

	Pause the execution (10s max) if any errors are displayed so the user
	has a chance to see them.

	* grub-core/kern/err.c (grub_err_printed_errors): New variable.
	(grub_print_error): Increment grub_err_printed_errors.
	* grub-core/normal/menu.c (grub_menu_execute_entry): Pause the
	execution if any errors were displayed.
	(show_menu): Remove old code for pause.
	* grub-core/normal/menu_entry.c (run): Likewise.
	* grub-core/normal/term.c (grub_normal_char_counter): Removed. All
	users updated.
	(grub_normal_get_char_counter): Likewise.
	* include/grub/err.h (grub_err_printed_errors): New external variable.
	* include/grub/normal.h (grub_normal_get_char_counter): Removed.