New functions with QT GUI:

- 3 new points mostly done:
      - OpenGL support enabled (windows are rendered using GPU)
      - Save current screen (with overlay and so on...) with shortcut CTRL+S
      - Text rendering (with any system font, and possibility to set the style - normal, italic,... - the weight - normal, bold, ... - the color, the spacing between letters, and so on...)

modules/highgui/src/window.cpp

@@ -189,11 +189,23 @@ int startWindowThread()
 }
 
 #if defined (HAVE_QT)
+
+void addText( const Mat& img, const string& text, Point org, CvFont font)
+{
+	CvMat _img = img;
+	cvAddText( &_img, text.c_str(), CvPoint(org),&font);
+}
+
 void displayStatusBar(const string& name,  const string& text, int delayms)
 {
 	cvDisplayStatusBar(name.c_str(),text.c_str(), delayms);
 }
 
+void createOpenGLCallback(const string& name,  OpenGLCallback callback, void* param)
+{
+	cvCreateOpenGLCallback(name.c_str(),callback, param);
+}
+
 void displayOverlay(const string& name,  const string& text, int delayms)
 {
 	cvDisplayOverlay(name.c_str(),text.c_str(), delayms);