t3311: Initial implementation

This module implements support for the Comet System T3311 Temperature
and Humidity transmitter.  It uses MODBUS over an RS232 serial port.

You must have libmodbus v3.1.2 (or greater) installed to compile and
use this driver.

Signed-off-by: Jon Trulson <jtrulson@ics.com>
Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>

src/upm.h

@@ -284,6 +284,12 @@
  * @ingroup byman
  */
 
+/**
+ * @brief Comet System
+ * @defgroup comet Comet
+ * @ingroup byman
+ */
+
 /**
  * @brief EpicTinker
  * @defgroup epict EpicTinker