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

If `pthread_create` fails, `newPin` will never get reset to -1 and process would hang. This change will return from `softPwmCreate` immediately if  `pthread_create` returns a non-zero value and avoid hanging forever.

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

for kernels 4.8 onwards.

Some very old stuff might break.

Additional fixes for the ISR code and some tweaks here and
there. I've removed the checks for some operations that might
fail when using the gpiomem interface - which is now the default
way of doing things - if your program segfaults, then you
may need to use sudo on it.

for the SPI code - it's mentioned in spidev.h but not used in the actual
kernel documentation example spi_test.c program )-:

to produce a nicer 'readall' output too.

It also understands new pins 53,54,55 and 56 in wiringPiSetupPhys()
mode to represent the pins on the P5 connector on the Rev 2 Pi's

Changes to pinMode() to allow new modes SOFT_PWM and SOFT_TONE.

bugfix in blink.sh - wring pin
improving the maxdetect routing - a little.
gpio pins

and an example.