Drag and drop in the Work Breakdown Structure working

[Simon Morris]

Hello,

Just to announce that in the trunk version of django-project-management
you are now able to drag and drop tasks to reorder them in the Work
Breakdown Structure.

By doing this the order is preserved next time you load the project up,
and also the PDF version of the Work Breakdown Structure is renumbered.

Tested in Firefox and IE but please let me know if that doesn't work
correctly

Thanks

~sm