Let all polygon ops start with a bounding box query

[asinghvi17]

If the bounding boxes of the two polygons don't intersect, we can immediately short-circuit the evaluation of any polygon set operation. Would give up to 1000x speedup in some cases, and of course more for really complex polygons.

[rafaqz]

Precalculating the extents may help if we're going to do this multiple time with the same obect

[skygering]

@rafaqz Would we then want to store the extent within the GI polygons? Would we always precalculate, or would this be a user choice? It would also be good to sort the polygons by extent when validating multipolygons. This would change the types of the returned polygons.

[rafaqz]

if you use tuples I think you can pass calc_extent=true to embed it for all nested geoms

[skygering]

See the conversation in #107 for more implementation details.