Fix remote data extracts

Rather than using Overpass, HOT maintains a copy of the planet updated every minute using a program called Underpass. This allows for SQL queries, large data extracts, and more control over the date returned by the query.

fix Overpass query

This improves the OverpassClient to work with a boundary from memory in addition to a file.

Refactor document and update

Create this as a new doc not linked to the Home.md doc, and update the content.

v0.1.0

First release.