modified submission reminders for rubric

Previously, the reminder students get when they leave the rubric
evaluation form without submitting will get an alert reminder. They
also get a message when a evaluatee's section is saved that shows up
for a very short period of time. I have modified the evaluation
reminder to be an alert message on the top of the form every time
a section is saved. The reminder also points out comments may be
missing if they are required and a comment section is left unfilled.
modified rubric evaluation form to not have default Likert answers

The rubric evaluation form has been modified to not have the lowest
rating set as default for the Likert question. Due to this change
all likert questions have to be answered before saving. A javascript
validation has been added. If a Likert question is left unanswered,
the question would be marked red and a warning message will appear
below the save button telling the student to answer all the questions
marked red before saving.
updated system tests including student_rubric

I have fixed rubrics view, which complained about an invalid variable
$event that is only used in the rubric evaluation form. I have also
updated some of the system tests to reflect minor changes made to
the interface.

I have added some new tests to student_rubric to reflect the changes
made. This include the new warning messages and unanswered likert
questions being marked red.