Register QObject classes as QML elements via macros

Using manual registration with qmlRegisterType (or
qmlRegisterUncreatableType) isn't ideal, because Qt Creator can't pick
up on it. When using the macros, autocompletion & unknown type warnings
in the code disappear.

columnslot.h

@@ -2,11 +2,14 @@
 #define COLUMNSLOT_H
 
 #include <QObject>
+#include <qqmlintegration.h>
 #include "playingcard.h"
 
 class ColumnSlot : public QObject
 {
     Q_OBJECT
+    QML_ELEMENT
+    QML_UNCREATABLE("Use C++ logic to instantiate")
     Q_PROPERTY(PlayingCard* card READ card CONSTANT)
     Q_PROPERTY(bool revealed READ isRevealed NOTIFY revealedChanged)
 

gamestate.h

@@ -2,12 +2,15 @@
 #define GAMESTATE_H
 
 #include <QObject>
+#include <qqmlintegration.h>
 #include "playingcard.h"
 #include "columnslot.h"
 
 class GameState : public QObject
 {
     Q_OBJECT
+    QML_ELEMENT
+    QML_UNCREATABLE("Use C++ logic to instantiate")
     Q_PROPERTY(QList<PlayingCard*> drawPile READ drawPile NOTIFY drawPileChanged)
     Q_PROPERTY(QList<PlayingCard*> throwawayPile READ throwawayPile NOTIFY throwawayPileChanged)
     Q_PROPERTY(QList<QList<ColumnSlot*>> columns READ columns NOTIFY columnsChanged)

main.cpp

@@ -15,9 +15,6 @@ int main(int argc, char *argv[])
         []() { QCoreApplication::exit(-1); },
         Qt::QueuedConnection);
 
-    qmlRegisterUncreatableType<PlayingCard>("Solitare", 1, 0, "PlayingCard", "PlayingCard cannot be directly created in QML. Use C++ logic to instantiate.");
-    qmlRegisterUncreatableType<ColumnSlot>("Solitare", 1, 0, "ColumnSlot", "ColumnSlot cannot be directly created in QML. Use C++ logic to instantiate.");
-
     GameState gameState;
     gameState.dealCards();
     gameState.drawNextCard();

playingcard.h

@@ -2,10 +2,13 @@
 #define PLAYINGCARD_H
 
 #include <QObject>
+#include <qqmlintegration.h>
 
 class PlayingCard : public QObject
 {
     Q_OBJECT
+    QML_ELEMENT
+    QML_UNCREATABLE("Use C++ logic to instantiate")
 
     Q_ENUMS(Value)
     Q_ENUMS(Suit)