code: public static PropertyLookup create(final File propfile, final IPropertyLookup defaultsLookup) {
          return new PropertyLookup(fetchProperties(propfile), defaultsLookup);
      }
docs: Calls base constructor with data from IPropertyLookup paramater as defaults. Defaults
  data is read via the {@link IPropertyLookup#getPropertiesMap()} method.
  
  @param propfile       File containing property data
  @param defaultsLookup IPropertyLookup of default properties
  @return lookup