Enhancement - Record::has

- Implemented Record::has which guarantees no autovivification of
  attributes.

src/Record.cpp

@@ -116,6 +116,16 @@ void Record::parse (const std::string& input)
                                    "Record not recognized as format 4");
 }
 
+////////////////////////////////////////////////////////////////////////////////
+bool Record::has (const std::string& name) const
+{
+  Record::const_iterator i = this->find (name);
+  if (i != this->end ())
+    return true;
+
+  return false;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 std::vector <Att> Record::all ()
 {