spaCy pipeline component?

[DanShatford]

Would it work to make the core geoparsing capability as a spaCy pipeline component or two?

This could help address #7, and make it easier for people to add their preferred entity extraction as long it gets saved in doc.ents and happens before the geoparsing.

Happy to help or make a PR if you this is something you'd accept. No bother if there's a reason you don't want to do this, or it's not possible.

Great work btw, thanks!