Complete rewrite (TypeScript)

[alanpoulain]

This PR provides a complete rewrite of GeocoderJS in TypeScript (and therefore a module support) and some more goodies (Mapbox, OpenCage and GeoPlugin providers, formatted address, time zone, bounds and country support).

I tried to not break everything and to follow the old API as much as possible.

Since the project seems not maintained anymore, I took the liberty to fork it and to publish it under a new name: Universal Geocoder (https://github.com/universal-geocoder/universal-geocoder-js).

I will maintain this branch (ts) without the specific changes for Universal Geocoder in case you want to revive the project.

Thank you for having creating this library and for maintaining the PHP version :slightly_smiling_face: