Adding figures to README.

README.md

bash/kitti/setup_dataset_kitti.sh

bash/nyu_v2/setup_dataset_nyu_v2.sh

bash/void/setup_dataset_void.sh

figures/figures/calibrated_backprojection_layer.png

figures/figures/calibrated_backprojection_network.png

figures/figures/overview_teaser.gif

figures/figures/poster.pdf

figures/figures/sparse_to_dense_pool.png

figures/figures/void_teaser_image_306.png

figures/figures/void_teaser_image_644.png

figures/figures/void_teaser_kbnet_output_306.gif

figures/figures/void_teaser_kbnet_output_644.gif

figures/figures/void_teaser_sparse_point_cloud_306.gif

figures/figures/void_teaser_sparse_point_cloud_644.gif

setup/setup_dataset_kitti.py

setup/setup_dataset_nyu_v2.py

setup/setup_dataset_void.py