Use MOC to enable clean and simple connection statements

The new (and old) connection syntax is too verbose:

connect(sender, &Sender::valueChanged, receiver, &Receiver::updateValue );

Even more so when overloads have to be explicitly specified:

connect(spinbox, static_cast<void (QSpinBox::*)(int)>(&QSpinBox::valueChanged), slider, &QSlider::setValue);

A possible solution, use a macro + MOC to generate the connection statement from a simpler expression:

Q_CONNECT(spinbox->valueChanged(int), slider->setValue)

Example features:

• detect if a pointer is used "objPtr->someSig" or an instance "obj.someSig" and use the & operator in case of the latter, less prone to errors

• detect if overload is specified with signal or slot parameter(s) and use static_cast to specify it

• make it work with non QObject derived classes methods, free functions and lambdas too, and from outside the scope of a QObject derived classes