make property scanner_type optional

source/RobotAPI/drivers/SickLaserUnit/SickLaserUnit.cpp

@@ -134,7 +134,7 @@ namespace armarx
         def->optional(properties.topicName, "topicName", "Name of the topic");
         //Scanner parameters
         def->optional(properties.devices, "devices", "List of Devices in format frame1,ip1,port1;frame2,ip2,port2");
-        def->required(properties.scannerType, "scannerType", "Name of the LaserScanner");
+        def->optional(properties.scannerType, "scannerType", "Name of the LaserScanner");
         def->optional(properties.timelimit, "timelimit", "timelimit for communication");
         def->optional(properties.rangeMin, "rangeMin", "minimum Range of the Scanner");
         def->optional(properties.rangeMax, "rangeMax", "maximum Range of the Scanner");