Fix BlackGui header includes

* Include only what is used
* Use forward declaration when possible
* Sorted includes

refs #598

src/blackgui/editors/aircrafticaoform.h

@@ -16,8 +16,13 @@
 #include "blackgui/editors/form.h"
 #include "blackmisc/aviation/aircrafticaocode.h"
 #include "blackmisc/statusmessagelist.h"
+#include "blackmisc/variant.h"
+
+#include <QObject>
 #include <QScopedPointer>
 
+class QWidget;
+
 namespace Ui { class CAircraftIcaoForm; }
 
 namespace BlackGui