Fixed change detection for top navigation and cancel button
Added change check to update attributes (bnc#887050)

In order to prevent wrong change events i have added a check to the
write attribute method that triggers an attributes change only if the
value really have been changed. This commit will fix
https://bugzilla.novell.com/show_bug.cgi?id=887050
Merge pull request #1096 from tboerger/feature/edit-notify-fix

Added change check to update attributes (bnc#887050)