JVET-AG0196 (Tests 5.1 and 5.2), JVET-AG0117 (Test 5.3), JVET-AG0143 (Test 3.1c), JVET-AG0100 (Test 3.2b*)

Merge of 5.1 5.2 5.3 3.1c 3.2b* (needed because of coupling on contexts retrain)