Add ncurses_backend feature flag to enable cursive/ncurses-backend

Similar to existing crossterm_backend and pancurses_backend.

Cargo.lock

@@ -722,6 +722,7 @@ dependencies = [
  "libc",
  "log",
  "maplit",
+ "ncurses",
  "pancurses",
  "signal-hook",
  "term_size",

Cargo.toml

@@ -80,6 +80,7 @@ alsa_backend = ["librespot-playback/alsa-backend"]
 cover = ["ioctl-rs"] # Support displaying the album cover
 default = ["share_clipboard", "pulseaudio_backend", "mpris", "notify", "termion_backend"]
 mpris = ["zbus"] # Allow ncspot to be controlled via MPRIS API
+ncurses_backend = ["cursive/ncurses-backend"]
 notify = ["notify-rust"] # Show what's playing via a notification
 pancurses_backend = ["cursive/pancurses-backend", "pancurses/win32"]
 portaudio_backend = ["librespot-playback/portaudio-backend"]