ds18b20: rewrite C++ to wrap C, add FTI, update examples

Previously, the C++ and C versions of this driver were separate.  Now
the C++ implementation wraps the C implementation.

In addition, the C++ init() function has been deprecated.  It
currently does nothing, and examples have been modified to remove it's
calls.  This function will be removed in a separate release.

The examples have been further modified to update all detected devices
and print their respective temperatures, instead of only reporting the
on the first device detected.

Signed-off-by: Jon Trulson <jtrulson@ics.com>

examples/c/ds18b20.c

@@ -56,7 +56,7 @@ int main(int argc, char **argv)
 
     printf("Found %d device(s)\n\n", ds18b20_devices_found(sensor));
 
-    // update and print available values every second
+    // update and print available values every 2 seconds
     while (shouldRun)
     {
         // update our values for all sensors