InstructorFeedbackResultsView: show the team ID of students who did not submit #2535

Resumed from #2687 
Fixes for #2535
The 'team' for instructors in the results page is "Instructors". Maybe we should standardize a team name for instructors and italicize it to make it different from normal teams?

@damithc 

![image](https://cloud.githubusercontent.com/assets/3910365/5548699/23540f86-8bb3-11e4-844b-dac8979f2155.png)