Fix depedence on now-private method
fix destroy function

- in jQuery UI 1.10.0 the destroy function is renamed in _destroy
- removing the useless .unbind(".nestedSortable") call
- add the removeData("ui-sortable") call to remove the remaining
"ui-sortable" data
- replace namespace for removeData (from nestedSortable to
mjs-nestedSortable)
Merge pull request #78 from chrjean/2.0alpha

fix destroy function