fixed changeMixevalEvaluationGradeRelease and

changeMixevalEvaluationCommentRelease by including the third
parameter for the function getResultsByEvaluatee for
EvaluationMixeval.
made some minor changes throughout the application

If a student submits after an instructor releases the comments or
answers from the individual group results, the button shows
unrelease comments or grades instead of releasing. I've fixed it
by setting the buttons to release when a minimum of one submission
is not released.

Included a javascript confirm for the drop action in go_to_class_list
so that students would not be accidentally unenrolled.

I've changed the wording for the confirm message for users/message
to have a gentler tone.

Added * to required questions for mix evaluation results.
fixed release buttons for simple and rubric evaluation results

Previously, the release buttons' actions (eg. release/unrelease)
depends on a boolean that is determined by the last
evaluation_simple or evaluation_rubric entry in the data array.
I've fixed that by multiplying all the booleans for the individual
release booleans for each user.

This is to accomodate for the possibility of a student submitting
after the instructor has already released the grades and/or
comments. If that's the case the button will be to release instead
of possibly unrelease.

I have also removed the formatMixevalEvaluationResultsMatrix
function and its test since it's no longer used.