Per column cart support checking and logic compression.

Conflicts:
	module/VuFind/src/VuFind/Controller/CombinedController.php
	themes/bootstrap3/templates/combined/results-list.phtml
	themes/bootstrap3/templates/combined/results.phtml
	themes/bootstrap3/templates/combined/stack-distributed.phtml
	themes/bootstrap3/templates/combined/stack-left.phtml
	themes/bootstrap3/templates/combined/stack-right.phtml
	themes/bootstrap3/templates/search/list-list.phtml
	themes/bootstrap3/templates/search/results.phtml