Notification of string changes

Author: Tim Hunt
MDL-42504 quiz autosave: alert users if connection lost.
When the auto-save fails, we alert the user that they may have lost their
internet connection so that they don't do more work that they might just
lose.


http://git.moodle.org/gw?p=moodle.git;a=commit;h=e9a504c2f811b3080bf54a47fe326bdfe7745fee
http://github.com/moodle/moodle/commit/e9a504c2f811b3080bf54a47fe326bdfe7745fee

+ 2.5 en [connectionok,mod_quiz]
+ 2.5 en [connectionerror,mod_quiz]