Merge branch 'fixBadContextInit' into 'master'

make the global context current from the beginning

See merge request !76

OpenFlipper.cc

@@ -537,10 +537,8 @@ int main(int argc, char **argv)
     QOffscreenSurface *surface = new QOffscreenSurface();
     surface->create();
 
-    QOpenGLContext context;
-    context.setScreen(screen);
-    context.create();
-    context.makeCurrent(surface);
+    //make the globally shared OpenGLContext current
+    QOpenGLContext::globalShareContext()->makeCurrent(surface);    
 
 #endif