no get_by_bbox function for skeleton

[xiuliren]

In the README.md, there is a get_by_bbox function for skeleton, but there is no such a function in the code!

If you are going to implement this function, will the skeletons crossing this bounding box included or not?

[william-silversmith]

Good question. I expect that skeletons crossing the bbox will be included. Without constructing a complete database, it would be difficult to exclude them. I'll hopefully correct this oversight soon.