Also adding in the stuff for /dev/gpiomem with warnings
and information in the gpio manual page (who reads that
though!)

Updated the gpio program to be device tree aware.

Added in generic 'blink' programs in the examples in C, RTB and Shell.
Updated wiringPi with a little big-file on the millis() function and
added in a new micros() function too.
Updated the examples with standard LGPL headers.
Added a new isr-osc.c test program - just for ISR timing purposes.

delayMicrosecondsHard re-written - again.
Added a serialRead example program, and added in the okLed
to the examples too.
Updated/checked some of the GPIO/PWM code.
Added in some experimental servo and tone generating code and
and example or 2.
Tweaks to the gpio command to correctly load the I2C modules too.