ncurses doesn't work for remote shells

[fhunleth]

Currently ex_ncurses uses the stdin/stdout of the console that started it. You can specify a different tty to initscr/1, but this doesn't help for the remsh case since there's no tty. This or some other way to remotely use an ex_ncurses-based UI would be very useful since the startup console is not always easy to access especially on some Nerves devices.