This module implements support for the DFRobot EC (Electrical
Conductivity) meter. It relies on the use of the DS18B20 UPM C module
for temperature gathering.
It has a pretty complicated calibration procedure which is somewhat
documented on the DFRobot wiki. Functions have been added to support
changing the various coefficients as desired.
Signed-off-by: Jon Trulson <jtrulson@ics.com>