Named wires have bugs

[dsharlet]

While working on #189, I'm finding that named wires had a lot of issues. In particular, when deleting or moving a named wire, the node it was attached to keeps the same name, even if the named wire moves to a new node. If the circuit were to simulate like this, it would behave as if the old node still had the named wire attached. I suspect there are many other bugs like this.

The only way to see this is via the tooltips that appear when hovering over a wire. When simulating, we clone and rebuild the circuit, which works around this issue.