QDeclarativePropertyMap changed

void valueChanged(const QString &key, const QVariant &value);
==>
void valueChanged(const QString &key);

Task-number: QTCREATORBUG-863
Reviewed-by: Friedemann Kleint

Task-number: QTCREATORBUG-948
Reviewed-by: dt

Update terminology QML project becomes Qt Quick project. Add information about creating Qt Quick applications.

New screenshots added for sections Setting Up a qmake Project and Quick Tour along with minor corrections in the document

Edit introduction to Quick Designer. Change product name to Quick Designer. Change terminology (widget becomes component). Update and add information about using Quick Designer. Update and add images.