QTI 2.1: feedback can be turned on/off for whole test

for questions items a feedback can be added. if it is added, it is also shown. for summative tests the feedback should often not be shown. to be able to use the same test it should be possible to hide feedback for the whole test.

• in options feedback for whole test can be enabled/disabled
• if disabled: no feedback is shown
• if enabled all feedback is shown
• default: summative tests feedback disabled, for formative tests feedback enabled