Removed unused confidence values and replaced with a disqualify boolean

The disqualify reason is purely for debugging.  This should help make it obvious why a plate candidate was rejected

src/openalpr/alpr_impl.cpp

@@ -152,7 +152,7 @@ namespace alpr
       lp.recognize();
 
       bool plateDetected = false;
-      if (pipeline_data.plate_area_confidence > 10)
+      if (!pipeline_data.disqualified)
       {
         AlprPlateResult plateResult;
         plateResult.region = defaultRegion;