MDL-31065 question stats: fix analysis of responses not matching a given answer

When shortanswer, numerical, calculated and calculatedsimple questions
did not have a '*' match-anything answer, then any student response that
did not match any of the teacher-given answers were classified as
'[No response]', which was not right.

This patch fixes that. Such responses are now classified as
[Did not match any answer].

While I was doing this, I noticed that the display of tolerance
intervals for numerical questions in the response analysis was horrible,
so I improved it.

question/type/questionbase.php

@@ -709,8 +709,10 @@ abstract class question_graded_by_strategy extends question_graded_automatically
 
         $ans = $this->get_matching_answer($response);
         if (!$ans) {
-            return array($this->id => question_classified_response::no_response());
+            return array($this->id => new question_classified_response(
+                    0, $response['answer'], 0));
         }
+
         return array($this->id => new question_classified_response(
                 $ans->id, $response['answer'], $ans->fraction));
     }