#41 Viewer allows illegal edits

[Jeremy LaCivita]

basically the cool features we've added to the viewers,
to let them edit annotations, instead of just view them:

drag and drop
the popup type menu

allows annotators to make edits that might be
undesirable in a certain scheme, like doing propbank,
you can re arange the tree with drag and drop.

we need to consider and prevent this sort of thing.