Slots added to GLViewer to force the update of focal, projection matrix or view matrix.

GLViewer/GLViewer.h

@@ -378,6 +378,10 @@ signals:
     | QT slot(s) |
     \************/
 public slots:
+    inline void                                 mustUpdateFocal()               { m_MustUpdateFocal = true; }
+    inline void                                 mustUpdateProjectionMatrix()    { m_MustUpdateProjectionMatrix = true; }
+    inline void                                 mustUpdateViewMatrix()          { m_MustUpdateViewMatrix = true; }
+
     inline void                                 emitScreenSpaceTranslation( const QVector2D& tr) { emit screenSpaceTranslation(tr); }
     inline void                                 emitViewRotationMatrixUpdated( const QMatrix4x4 &r ) { emit viewRotationMatrixUpdated(r); }