Add variable batch for detector update

Signed-off-by: Micaela Verucchi <micaelaverucchi@gmail.com>

demo/demo/demo.cpp

@@ -111,7 +111,7 @@ int main(int argc, char *argv[]) {
             break;
     
         //inference
-        detNN->update(batch_dnn_input);
+        detNN->update(batch_dnn_input, n_batch);
         detNN->draw(batch_frame);
 
         if(show){

demo/demo/map.cpp

@@ -144,7 +144,7 @@ int main(int argc, char *argv[])
 
         //inference 
         detected_bbox.clear();
-        detNN->update(batch_dnn_input, write_res_on_file, &times, write_coco_json);
+        detNN->update(batch_dnn_input,1,write_res_on_file, &times, write_coco_json);
         detNN->draw(batch_frames);
         detected_bbox = detNN->detected;