Add < operator to PublicSensor class

lib/include/dcdb/sensorconfig.h

@@ -69,6 +69,8 @@ public:
     
   PublicSensor();
   PublicSensor(const PublicSensor &copy);
+    
+  inline bool operator <  (const PublicSensor& rhs) const {return name <  rhs.name;}
 };
 
 /**