Update 3d detection

This commit updates the CenternetDetection3d class and fixes
some bugs.

It also removes the resnet101 network for CenterNet 3D.
This network doesn't exist.

Signed-off-by: Davide Sapienza <sapienza.dav@gmail.com>

include/tkDNN/CenternetDetection3D.h

@@ -61,6 +61,8 @@ private:
     #endif
     cv::Mat r;
     float *d_ptrs;
+    
+    cv::Size sz_old;
 
     cv::Mat src;
     cv::Mat dst;