1. remove "no reply" from sender name and sender email
2. fix related tests
move emphasis from date/time to timeTaken
Moved BackDoorTest and GodModeTest out of staging tests.
Merge branch 'master' of https://github.com/TEAMMATES/repo
1. add background colour for table cell
change magic numbers into constant
Merge pull request #2268 from TEAMMATES/Issue2261

adminActivityLog: de-emphasize date/time, emphasize time taken #2261
Merge pull request #2267 from TEAMMATES/Issue2262

remove 'no reply' from TEAMMATES emails #2262
add course delete cascade logic test
Delete existing dataBundle only when necessary, omit waiting for persistence since it is alrady done at EntitiesDb level, add wait functions for ajax calls to prevent test failures.
Fix previous merge error
instructors delete cascade test
Fix typo in TimeHelper
studentLogic test
Merge branch 'dev' into 74590202

Conflicts:
	src/main/java/teammates/logic/core/StudentsLogic.java
Merge branch 'master' into 74590202
Fix tests
dev green
Merge branch '74590202' into dev
Add test for template sessions