[TODO] More readable time

[sunner]

The post time of questions is printed ugly. It should be changed to:

1. now if it is posted just now.
2. 2 hours and 40 mins ago if it was posted less than 24 hours ago
3. FULL DATE if it has been posted for more than 24 hours

The patch should be on the following line of code in view.php:

$a->time = userdate($question->time).'&nbsp('.get_string('early', 'assignment', format_time(time() - $question->time)) . ')';