Bounding Boxes

Have an ever increasing number of labeled number crops*. Adding bounding boxes opens up digit-level recognition and should allow current dataset to function for add same-sized digits on the screen.

- But how do I add bounding boxes?
- And does adding them on only some (or even most) images hurt those where digits are not detected?
- Mostly black or dark gray backgrounds with bright white numbers may be the place to start, but it's not the norm.

...
- *[`stable_numbers`](https://github.com/gumdropsteve/warzone/tree/crop_approach/media/stable_numbers/number_crops) now over 15k, and becoming more stable (new method to recrop og screenshots as issues are resolved or different methods prove more successful at cropping correctly). + [`digits_only`](https://github.com/gumdropsteve/warzone/tree/crop_approach/media/digits_only) + [`kills_only`](https://github.com/gumdropsteve/warzone/tree/crop_approach/media/kills_only) puts current total labeled near 30k.