Router assertion often false, during object deletion (at least through GUI, perhaps also programmatically)

[skieffer]

The assertion comes at the beginning of the Router::deleteShape(ShapeRef *shape) method:

void Router::deleteShape(ShapeRef *shape)
{
// There shouldn't be add events events for the same shape already
// in the action list.
// XXX: Possibly we could handle this by ordering them intelligently.
COLA_ASSERT(find(actionList.begin(), actionList.end(),
ActionInfo(ShapeAdd, shape)) == actionList.end());