Support autojump in popup SelectView (#793)

For now, only support autojump when the popup is closed, and not inside
the menu popup itself.

Note that autojump fires the select callback, while popup mode previously
only fired the submit callback.

cursive-core/src/views/select_view.rs

@@ -814,7 +814,8 @@ impl<T: 'static + Send + Sync> SelectView<T> {
         })
     }
 
-    // A popup view only does one thing: open the popup on Enter.
+    // A popup view opens the popup on Enter, and also applies autojump if
+    // enabled.
     fn on_event_popup(&mut self, event: Event) -> EventResult {
         match event {
             // TODO: add Left/Right support for quick-switch?
@@ -824,6 +825,7 @@ impl<T: 'static + Send + Sync> SelectView<T> {
                 position,
                 offset,
             } if position.fits_in_rect(offset, self.last_size) => self.open_popup(),
+            Event::Char(c) if self.autojump => return self.on_char_event(c),
             _ => EventResult::Ignored,
         }
     }