Include missing header files (#607)

- Explicitly include headers which is automaticaly
  QMake handle.

Signed-off-by: Hiroshi Miura <[email protected]>

src/vnavigationmode.h

@@ -5,6 +5,7 @@
 #include <QVector>
 #include <QMap>
 #include <QList>
+#include <QObject>
 
 class QLabel;
 class QListWidget;

src/vnotebookselector.h

@@ -2,6 +2,7 @@
 #define VNOTEBOOKSELECTOR_H
 
 #include <QComboBox>
+#include <QKeyEvent>
 #include <QVector>
 #include <QString>
 #include "vnavigationmode.h"