Fix PCA demo for QGLViewer 2.7

Principal_component_analysis/demo/Principal_component_analysis/MainWindow.cpp

@@ -181,7 +181,11 @@ void MainWindow::on_actionCopy_snapshot_triggered()
   QClipboard *qb = QApplication::clipboard();
   m_pViewer->makeCurrent();
   m_pViewer->raise();
+#if QGLVIEWER_VERSION >= 0x020700
+  QImage snapshot = m_pViewer->grabFramebuffer();
+#else
   QImage snapshot = m_pViewer->grabFrameBuffer(true);
+#endif
   qb->setImage(snapshot);
 	QApplication::restoreOverrideCursor();
 }

Principal_component_analysis/demo/Principal_component_analysis/Viewer.h

@@ -1,6 +1,6 @@
 #ifndef VIEWER_H
 #define VIEWER_H
-
+#include <QMap>
 #include <QGLViewer/qglviewer.h>
 
 // forward declarations