added unit test for jointLimitConstraintsmex
added unit test for jointLimitConstraintsmex

hanssusilo/drake,billhoffman/drake,tkoolen/drake,edowson/drake,crogers3/drake,billhoffman/drake,crogers3/drake,edowson/drake,hanssusilo/drake,scottviteri/drake,psiorx/drake,thientu/drake,edowson/drake,billhoffman/drake,scottviteri/drake,astrorog/drake,psiorx/drake,billhoffman/drake,thientu/drake,psiorx/drake,hanssusilo/drake,edowson/drake,hanssusilo/drake,tkoolen/drake,billhoffman/drake,scottviteri/drake,sheim/drake,billhoffman/drake,psiorx/drake,thientu/drake,astrorog/drake,sheim/drake,tkoolen/drake,sheim/drake,astrorog/drake,edowson/drake,tkoolen/drake,psiorx/drake,astrorog/drake,sheim/drake,thientu/drake,billhoffman/drake,crogers3/drake,crogers3/drake,sheim/drake,sheim/drake,psiorx/drake,crogers3/drake,astrorog/drake,astrorog/drake,hanssusilo/drake,scottviteri/drake,edowson/drake,hanssusilo/drake,sheim/drake,scottviteri/drake,scottviteri/drake,sheim/drake,psiorx/drake,edowson/drake,tkoolen/drake,thientu/drake,hanssusilo/drake,tkoolen/drake,psiorx/drake,scottviteri/drake,crogers3/drake,edowson/drake,crogers3/drake,crogers3/drake,astrorog/drake,tkoolen/drake,hanssusilo/drake,thientu/drake,thientu/drake,billhoffman/drake