Build system changed to Cmake, ORM changed to QxORM, Qt6 compatibility.

core/igridform.cpp

@@ -19,7 +19,7 @@ IGridForm::IGridForm(QWidget *parent) :
     ui->filterWidget->setVisible(false);
     m_contextMenu = new QMenu(this);
     m_contextMenu->addAction(ui->actionSelectColumns);
-    m_form = NULL;
+    m_form = nullptr;
 
     m_columnDialog = new ColumnDialog(this);
     connect(m_columnDialog, SIGNAL(accepted()), this, SLOT(columnsAccepted()));
@@ -29,7 +29,7 @@ IGridForm::IGridForm(QWidget *parent) :
 
 IGridForm::~IGridForm()
 {
-    if (m_varFiller != NULL)
+    if (m_varFiller != nullptr)
     {
         delete m_varFiller;
     }