Fix BlackGui header includes

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

refs #598

src/blackgui/components/simulatorselector.h

@@ -12,8 +12,12 @@
 
 #include "blackgui/blackguiexport.h"
 #include "blackmisc/simulation/simulatorinfo.h"
-#include <QScopedPointer>
+
 #include <QFrame>
+#include <QObject>
+#include <QScopedPointer>
+
+class QWidget;
 
 namespace Ui { class CSimulatorSelector; }