Handle bounding boxes on the edge properly

[shoumikchow]

Labels on the edge of the box aren't handled properly.
If an object detection model detects an image at the edge of the frame, there is a chance that some portions of a bounding box is outside the frame itself. That is, some of xmin, xmax, ymin, ymax might be negative or larger than the image dimension itself. In cases like these, OpenCV handles it by not drawing the bounding box at all.

Ideally, it should draw the lines that are outside the image dimensions along the edge.

[shreyasvedpathak]

Hey, I would like to try this issue. Can I go ahead?

[shoumikchow]

Absolutely! Feel free to fork and submit a PR.

[shreyasvedpathak]

Please check #8