Initial code for contribution question
front-end for adding contribution question
Instructor can add contribution question
Merge branch 'FeedbackSessions' into 72854604
Fixes for contribution qn visibility options
fix for contribution qn visibility - recipient can see recipient name checkbox
Add contribution question submission templates
Merge branch 'master' into 72854604

Conflicts:
	src/main/java/teammates/ui/controller/FeedbackSubmissionEditSaveAction.java
Can submit contribution question response
add validation rules for contribution question
Add additional info to show question type. minor change to question name.
Change contribution question csv answer to use string, equal share format.
Initial code for contribution question stats
Add working stats for contribution question
Hide helping info
Fix issues regarding visibility and generating stats for contribution question.
Refactor code, changes styles.
Allow stats to be view dependent. Show contribution stats only in question view
Merge branch 'dev' into 72854604
Add abbr for CC, PC in contribution question stats
Add test for contrib qn to FeedbackResponseDetailsTest