Draggable Incorrectly calls template init/update

[rposener]

When using draggable binding, it incorrectly uses template binding, but does not need to control the contents. This becomes an issue as it changes the context, and removes named items. Consider this example:

<tbody data-bind="foreach:{data:staff, as:'st'}">
    <tr>
        <th data-bind="text:st.Name"></th>
        <!-- ko foreach:{data:weeks, as:'wk'} -->
        <td data-bind="droppable:$component.dropTo.bind($component, {staff:st, week:wk})">
            <div data-bind="draggable:{staff:st, week:wk}">
                <span data-bind="text:$component.getCell.bind($component, {staff:st, week:wk})"></span>
            </div>
        </td>
        <!-- /ko -->
    </tr>
</tbody>

The span in here does not work, due to the template use in the draggable. I cannot see a valid reason for it in other cases. Will submit a pull request with this change.