fix panic

Signed-off-by: Frank Villaro-Dixon <frank@villaro-dixon.eu>

src/ui.rs

@@ -147,11 +147,13 @@ impl BeoUi {
                 // TODO: pass event to current app
             }
         }
-        println!(
-            "Current app {:?} - VIEW: {:?}",
-            self.current_app().unwrap().name(),
-            self.current_app().unwrap().get_current_view()
-        );
+        if let Some(app) = self.current_app() {
+            println!(
+                "Current app {:?} - VIEW: {:?}",
+                app.name(),
+                app.get_current_view()
+            );
+        }
     }
 
     pub fn draw<T: Renderer>(&self, canvas: &mut Canvas<T>, fonts: &Fonts) {