Add test for dragging while scrolling
Add test for dragging while scrolling

jgwhite/ember-sortable,tim-evans/ember-sortable,raelbr/ember-sortable,dianafa/ember-sortable,dianafa/ember-sortable,hilotus/ember-sortable,tim-evans/ember-sortable,jgwhite/ember-sortable,hilotus/ember-sortable,raelbr/ember-sortable