fix sortable vs draggable issue
fix sortable vs draggable issue

using the undocimented 'dropBehaviour': true of sortable to disable
mix-and-match with a regural jQueryUI droppable


Former-commit-id: d3ee03bddcf51549fe68569c8d41151a4bf70b05
webgme/webgme-engine,webgme/webgme-engine,webgme/webgme-engine