This is a general tidyup to detach this fork better from Gordon, who was (and perhaps still is) completely inundated with WiringPi-related support questions.

This changeset includes a number of tweaks which should reduce support burden on Gordon. I believe they are essential if we plan to release a new debian package.

They should - hopefully - not reduce or make ambiguous the origins of this code while achieving the above.

* Remove Gordon's email address from all source files to avoid support queries finding their way to him
* Update wiringPi URLs to the GitHub repository to try and keep bugs/issues within the fork
* Bump version to 2.70 ready for a debian package release
* Update debian package maintainer info, add bugs & homepage URLs to this repository

* Changes to support the Zero 2 W (model type 18|0x12)

* Increment version in version.h

* Increment version in debian-template/wiringPi/DEBIAN/control

* Increment version in VERSION as well - I keep missing places where this number is defined

* Increment VERSION_MINOR, missed in previous commits; add missing Pi Z2W model name to piModelNames

Co-authored-by: schwartz <pi@schwartz>
Co-authored-by: PumpkinPi <jack@mirkwood.net>