update object detection evaluation script

[avavavsf]

@BichenWuUCB KITTI update their object detection evaluation script on April 25, Which I believe corresponding to file ./src/datasets/kitti_eval/cpp/evaluate_object.cpp.

Maybe you want to update it. http://www.cvlibs.net/datasets/kitti/eval_object.php

In addition: Can you explain why did you change the image resolution and padding strategy?

[BichenWuUCB]

Hi

Sorry for the delay in replying. Thanks for letting me know. I'll take a look into that and integrate the updated evaluation script.

Yes, I changed image resolution (1242x375 -> 1248 x 384) and padding (from "valid" to "same") such that the last layer's feature map dimension is exactly 1/16 of the image resolution.