implemented labels for comments for answers (replies) from

evaluations and self-evaluations

- split the dataformat for PostsForAnswersAndPostsForComments and
PostsForQuestionsAndPostsForComments
- added the evaluation/selfeval attributes to the
PostsForAnswersAndPostsForComments
- added labels replies from evaluation and self-evaluation. Currently
we assume a reply can only be one of the two types therefore, the
logic is simple ng-if statements.
- I've also hid the edit/delete links from the user if the reply is
an evaluation or a self-evaluation
refactored self evalaution backend structure

- created a relationship model between SelfEvaluationTypes and PostsForQuestions
	- this allow the flexibility of more than one self
	evaluation types being attached to a question
- created some upgrade script and some constants in the model for
the comparison self-evaluation. However it is now commented out because
it will not be implemented yet
- ordered the returned list of self evaluation types by their name
- fixed changing self evaluation setting in editing questions
- database UPGRADE is required