dynamic adding of xdr boat data for implemented n2k conversions

lib/xdrmappings/GwXDRMappings.cpp

@@ -188,6 +188,10 @@ GwXDRMappingDef *GwXDRMappingDef::fromString(String s)
             return NULL;
         }
     }
+    if (rt->direction == GwXDRMappingDef::M_DISABLED || rt->xdrName == ""){
+        delete rt;
+        return NULL;
+    }
     return rt;
 }
 String GwXDRMappingDef::getTransducerName(int instance)

lib/xdrmappings/GwXDRMappings.h

@@ -166,7 +166,7 @@ class GwXDRFoundMapping : public GwBoatItemNameProvider{
         String buildXdrEntry(double value);
         //boat Data info
         virtual String getBoatItemName(){
-            return getTransducerName();
+            return String("xdr")+getTransducerName();
         };
         virtual String getBoatItemFormat(){
             return "formatXdr"+type->xdrunit; //TODO: use the type def for the correct format