[apps/code] Handle Home event when in the toolbox

If editing a script, the empty space at the end of the script should be
moved to the end of the storage.

apps/code/app.cpp

@@ -105,6 +105,10 @@ bool App::handleEvent(Ion::Events::Event event) {
   return false;
 }
 
+void App::willExitResponderChain(Responder * nextFirstResponder) {
+  m_menuController.willExitApp();
+}
+
 Toolbox * App::toolboxForInputEventHandler(InputEventHandler * textInput) {
   return &m_toolbox;
 }