Extend LinuxFS Providers for GPIO, PWM, Serial

[pi4j]

Extend LinuxFS Providers for GPIO, PWM, Serial

[FDelporte]

Feedback from @eitch

we have the following package:
src/main/java/com/pi4j/plugin/linuxfs/provider/gpio/digital

Those providers need to be extended similar to the classes in
src/main/java/com/pi4j/plugin/pigpio/provider/gpio/digital

So you would need to use class com.pi4j.plugin.linuxfs.provider.gpio.LinuxGpio for the implementation. This class seems to already be implemented, so maybe you just need to wire up the provider(s) with this class

or maybe we can use the following 1.4 C classes for this all:
pi4j-native/src/main/native/com_pi4j_wiringpi_GpioUtil.c

looking at this c file, then it doesn't use wiringPi at all, just does native calls
if using the c code, then i think code can be copied, you'll need to modify function names etc., but the compilation is already configured. maybe you will need to modify the Makefile