Fix samples header includes

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

refs #598

samples/hotkey/main.cpp

@@ -12,6 +12,7 @@
 
 #include "blackgui/components/settingshotkeycomponent.h"
 #include "blackgui/guiapplication.h"
+
 #include <QApplication>
 
 using namespace BlackGui;