Add example InteractivePWM

This example demonstrates how a changing slider can
be used to change the brightness of the RGB led on the Bacon Cape.
Pressing the button changes the color of the LED.
Move delay function to wiring.c

delay() and delayMicroseconds() to wiring.c from sysfs.c
Add Math functions and constants to linux-virtual

define statements for min, max, abs, PI, etc
Add missing headers to wiring.c

headers for time functions
Merge branch 'master' of github.com:prpplague/Userspace-Arduino
Add bit manipulation functions

lowByte,highByte, bit read,set,clear and write functions
Add map function to WMath

new file WMath.h.
Change adc sysfs dir and increase size of MAX_BUF

ADC values are now retrieved from the IIO sysfs abstractions, rather than
from the adc helper. The new range is 0 to 4095. The size of MAX_BUF had to be increased
to accomodate the *large* filepath.
Change ADC channel filename

The ADC filenames now reflect the changes made earlier, with ADC values now
being obtained from the IIO sysfs entries instead of the adc helper entries.
Change scaling algorithm in analogRead

The new scaling algorithm is more correct, as suggested by Matt Porter
and Andrew Bradford. It scales down from (0 to 4095) to (0 to 1023).
Minor change to 7segment

Modify if to take care of end condition of slider
Remove comments in PWM example

remove redundant pinMode comments for analogWrite
Change scale of analogWrite to 8bit

change PWM example to reflect new input range
Add analogReadResolution and update analogRead

The function analogReadResolution() is able to change the resolution
of the ADCs. The default resolution is 10 bits. Anything greater than
12 bits will be appended by zeros.
Add analogWriteResolution function

Function to change the resolution of analogWrite function using analogWriteResolution
Add functions randomSeed and random to WMath.cpp

These functions use stdlib.h to generate random numbers
Some refactoring in WMath.cpp
Change location of include in virtual_main

The header WMath.h belongs inside the condition #ifdef __cplusplus
since the source is a .cpp file.
Shift declarations of delay functions to wiring.h

The definitions of the delay functions were already shifted to wiring.c
but the prototypes were still present in sysfs.h