max5847: add sample

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

src/max5487/max5487.h

@@ -43,6 +43,7 @@ namespace upm {
  * PMOD module](http://datasheets.maximintegrated.com/en/ds/MAX5487PMB1.pdf)
  * from the analog PMOD kit.
  *
+ * @snippet max5487.cxx Interesting
  * @image html max5487.jpeg
  */
 class MAX5487 {