account for rounding in point cloud projection

[tom-bu]

The current code still considers a uv point that rounds up to the img width/height as valid. This causes errors when you try to run draw_ground_pts_in_image() in the ground_visualization.py.

[johnwlambert]

Thanks for the PR, @tom-bu. Would you mind adding a small unit test to your PR that fails without your change, and passes with your change?

[tom-bu]

Hi John, I have added a unit test. Let me know if it's what you're looking for. Thanks.