unit test for evaluation; sorting on product and evaluation

unit test for evaluation; 
sorting on product and evaluation
We don't need all this. Use `SelectList` in controller, it has a default option. See [EvaluationsController.cs#L101](https://github.com/uta2014/RequirementGathering/blob/466aad029bbe777bf5fb632ac805cb5ededdbe6c/RequirementGathering/Controllers/EvaluationsController.cs#L101) and its corresponding view (press Ctrl+M+G).