Fix build with Qt 5.5

--- a/src/videoencodingprofiles.h
+++ b/src/videoencodingprofiles.h
@@ -21,6 +21,7 @@
 #define VIDEOENCODINGPROFILES_H
 
 #include <QMap>
+#include <QObject>
 #include <QString>
 #include <QStringList>