New version needs WiringPi, but not the original version that got discontinued. There's an active fork of WiringPi which also provides `.deb` files, so check whether this new version is installed first before compiling locally a static version and using it.
Other modifications:
* modified the installation/build to use `$md_build` and handle the installation ourselves, instead of using the upstream `make` targets. This means the driver is copied to `/opt/retropie` (just like `xboxdrv`) instead of being located in `/usr/local`.
* added a `systemd` unit file to start the driver and don't rely on the upstream `rc.d` service scripts.
