changed behaviour re detection threshold

Before: the pose estimation was not computed if the confidence for the bounding box detection was below the bbox threshold, but the bounding box was still shown.
For a detection threshold = 95%:

Now: the bounding box is not shown if the detection confidence is below threshold

app.py

@@ -296,7 +296,7 @@ def predict_pipeline(img_input,
                                          dlc_proc)
 
         # Produce final image
-        img_background = Image.fromarray(md_results.imgs[0]) # img_input?
+        img_background = img_input # img_input or Image.fromarray(md_results.imgs[0])? 
         for ic, (np_crop, kpts_crop) in enumerate(zip(list_crops,
                                                       list_kpts_per_crop)):