This adds initial support for the DS2413 Dual Channel Addressable
Switch. This is a Dallas Semiconductor 1-wire compliant device
providing access to 2 open-drain GPIOs.
https://learn.adafruit.com/adafruit-1-wire-gpio-breakout-ds2413/overview
This driver requires One-Wire over UART support in MRAA (PR #415)
which is not yet merged.
Signed-off-by: Jon Trulson <jtrulson@ics.com>
