fixed evalcomments test for python 3.3
Ticket #140

- implemented normalized score - eg. score / max score
- replaced/inserted scores in the following screens
	- question
	- evaluation results
	- reports (csv)
	- participation (sortable)
- if answers were not evaluated - have 'Not Evaluated'
- if answer was not submitted - have 'No Answer'
- normalized score is a hybrid property in the Scores model
	- it uses a new hybrid property - max score - within
	CriteriaAndPostsForQuestions
Ticket #142

- removed student number column for participation screen because
student numbers are only used in the groups import and report export
- added "flagged" column to tell instructors which students' answers
are flagged.