Header: Make warning about closing the tab pop up only if user edited the tab

Reported-by: bnurbekov, lhnguyenduc
Signed-off-by: Batyrlan Nurbekov <bnurbekov@wpi.edu>, Long Nguyen Duc
Hoang <lhnguyenduc@wpi.edu>
Fixed merge conflict in NewGameTab.java
Commited by: Alec Thompson - ajthompson
Fixed merge conflict with NewGameTab.java
Commited by: Alec Thompson - ajthompson