disabled evaluation submit button after submission is made.

It has been reported that students are getting confused with the
warning message saying that the answer pair they have just evaluated
has already been evaluated before; therefore the submission failed.
However, what really happened, is that the student submitted multiple
times, so the first submission was successful and any subsequent submission
caused the error/warning messages.

Now, I have implemented the "submitted" boolean to prevent this problem
from happening. This implementation is actually done for multiple forms
in the application.
removed the the brief moment where the submit button re-enables.
First implementation of the judgement comment view/UI

I wrote three new api functions to get the required information for
this view, which includes:
- in the answer module, I create a function that returns the answers'
authors' full names indexed with the PostsForAnswers id
- in the evalcomment module, I created a basic function that returns
all of the judgement comments belonging to a question
	- there was a typo for the dataformat, which has been fixed
	(judgements --> judgement)
- in the new answerpairing module, I've created a nested list of
the answers and the answers they have been paired with.
	- this might not be the best way of helping to generate the
	second author filter list; therefore I may remove this function,
	when I come up with a better and faster method

Basically, the current view is very basic with three filters: the criterion,
the first answer author and the second answer author. Currently, judgement
comments of different criterion cannot be view at the same time. If this is
required, we can change the criterion filter to have a null option.

Things that still need to be done:
- button to access the page
- UI - showing the answers
- tests for new api functions
added new tests and permissions checking for some api functions

- I have added permissions check for judgement comments
	- GET - need to be able to MANAGE judgement comments
		- instructor/TA
	- POST - need to be able to CREATE judgement
		- student
- I have written tests for:
	- judgement comments - GET / POST
	- answers authors - GET
Merge branch 'judgement_fail_error' into develop