Suggestion: Add an import JSON matrix feature

Hi Xun Li:

This isn't an issue, but a suggestion. I have used MapBox's distance matrix in the past to find walking distances for parks in Maryland. The output is a networked distance matrix in JSON format that uses an OSM back-structure to find the distances and times. All it is a a JSON file (which is great!). Would it possible to allow GeoDa to import distance-matrix JSON files? It certainly would make my life easier, and open up a world of research questions.

The issue names no file, test, or entry point. Start by confirming the MapBox distance-matrix JSON format and reviewing GeoDa's existing import paths; done means GeoDa can import the specified JSON data for use as a distance matrix.

Written by the indexing model from the issue text.