Changeset 6586

#1541

• Updated code to reflect what Eric Taillard's code does at ​http://mistic.heig-vd.ch/taillard/codes.dir/tabou_qap.cpp which is however not quite what is described in the paper.
• Updated the swap2 move evaluator to perform move evaluations in O(1) for several cases by memorizing the move quality of the previous iteration
• Added a unit test to test the new faster evaluation
• Changed the robust taboo search to use this faster evaluation
• Renamed some operators (dropping the QAP pre- and postfix)