Install targets and files in default Runtime and Development CMake
components to determine files included in the two Debian packages.
Move to CMake minimum version to 3.12 to allow using NAMELINK_COMPONENT
option in install() allowing adding .so files in a separate component,
Developement here.
Use CPack to build the two Debian packages.

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

* Fix for multiple definition of comDat

Added gpio readall support for the Pi 0W.

Added fixed for a few minor things. pin driver for rht03/dht type
sensors. Network stuff is experimental - for now.