Connect QObject signal to non QObject class.

Usually you need to derive from QObject and use the Q_OBJECT macro to connect to some slot in your class.
But sometimes you want to connect a QObject signal to do something in a non QObject class.

There are several posible reasons to not derive from QObject or use the Q_OBJECT macro, but in any case you can connect to a non QObejct class using lambdas:

```c
  // Connect to menu action

  QMenu* menu:

  QAction* myAction = menu->addAction( QIcon(":/myIcon.svg"), "Do something" );

  QObject::connect( myAction, &QAction::triggered, [=](){ myFuncion(); });



  // Connect to QPushButton

  QPushButton* button = new QPushButton();

  QObject::connect( button, &QPushButton::released, [=](){ onButtonReleased(); });
```