Short-term fix for wire hovering bug

[sjbreiner]

There is currently a bug (#117) where wires in DWD are not hoverable/clickable after they are drawn.

I've tracked it down to the removal of the Interactable attribute at the end of the drag, which doesn't trigger an update. As a short-term fix, I am setting the value to true at the end of the drag instead, but this is just a short-term fix, as attribute removal should be triggering the update.

The problem isn't showing up in simplepetri, which calls the same dragEdge method, but without the bells and whistles (port lifting, type propagation).

[sjbreiner]

There are a few other minor changes:

• added handlers to the text label of wires
• Reverted debug to print internal scala state rather than json