Disable the creation of evaluations on the UI side.
an unregistered student can now view/submit feedback sessions for open session
student can now view results of a feedback session
now emails include the links to the unregistered actions
ported login filter to action level check
Merge branch 'dev' into 74749654

Conflicts:
	src/main/java/teammates/logic/core/Emails.java
Merge branch 'FeedbackSessions' into 74673764
Some UI changes for replacing evaluations
basic working version of ajax adminActivityLogPage
Add creating feedback sessions based on templates
Change in wording
Fix some tests
Change tooltip, replace references to instructor evals page
1. do some refactoring
2. fix the related tests
change testing-purposed search limit back to original
1. change save to submit in feedback submit pages
2. fix related tests
1. change "submit" to "start submission"  in student Home Page
2. fix related tests
Fix tests
instead of sending two mails, add admin email as BCC
Modifications to tests