Make the keys return their inner error, if any. For example, when permission to access the TTY is denied, don't loop infinitely and instead return to the outer scope to error and exit (or not) there.

src/input.rs

@@ -19,7 +19,7 @@ impl<R: Read> Iterator for Keys<R> {
             match self.iter.next() {
                 Some(Ok(Event::Key(k))) => return Some(Ok(k)),
                 Some(Ok(_)) => continue,
-                e @ Some(Err(_)) => e,
+                Some(Err(e)) => return Some(Err(e)),
                 None => return None,
             };
         }