Lesson detailed statistics not displayed for whole class

Lesson detailed statistics not displayed for whole class.
See this discussion: http://moodle.org/mod/forum/discuss.php?d=183600

1.- Suggested fix (for moodle 2.0 and 2.1)
in mod/lesson/report.php, line 563
change

if (!empty($page->answerdata) && isset($page->answerdata->response)) {

to:

if (!empty($page->answerdata) && (empty($userid) || (!empty($userid) && isset($page->answerdata->response)))) {

2.- Plus: when student did not answer a question, in the Detailed (individual) statistics it would be nicer to display "Did not answer this question." rather than "0".
in mod/lesson/report.php, line 577 change

$table->data[] = array(0, " ");

to:

$table->data[] = array(get_string('didnotanswerquestion', 'lesson'), " ");