Comparison with other libraries

[asinghvi17]

https://github.com/kadyb/vector-benchmark has a bunch of comparisons in the vein of the Julia performance plot, for basic vector geometry ops (no polygon ops, just distance, contains, intersect, reproject/transform, buffer, and IO).

I opened a PR kadyb/vector-benchmark#12 to add GeometryOps benchmarks here as well, but even if that doesn't get merged there we can still run those benchmarks, potentially every release or commit to master (or just when manually requested) over here:

If anyone here knows of other good benchmark sources for geometries, please let me know!

[asinghvi17]

Should we add this plot as a static plot to the README/docs?

[rafaqz]

This is readme material for sure.