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.