fixed mixeval results for students

Due to moving most of the queries for results from controllers/
components/evaluation.php to the different models, most of the
mixeval results page for students have invalid indices are variables.
I have fixed this by calling the required functions from the models.
Since most of the functions called in the component was not from
evaluation.php but from other models I have now removed the
formatMixevalEvaluationResult function and instead called the functions
from the evaluations_controller.

I have also fixed minor bugs such as the percentage given to each
student does not account for penalty if penalty exists. I have
also fixed the "Above Average" and "Below Average" text to be printed
on the actual total (after penalty) instead of the original since
the group average is based on the after penalty totals. Lastly,
I have commented out the code that prints information about
"Average Percentage Per Question".