[Feature Request]: Add route lines to map with Signal Quality coloring

[jamon]

Description

It would be useful to be able to see route lines on the map, and to see the signal quality of those links.

I've taken a first pass at adding this, which includes support for direct links and links that are discovered via NeighborInfo packets. Direct routes are shown in bold lines, NeighborInfo ones in thin lines. Currently I time out direct connections after 20 minutes if they haven't been seen. I'm not currently timing out NeighborInfo messages, but new ones will replace their old counterparts (the logic here is that those connections are probably still valid, even if you haven't heard about them in a while)

Adding lines for successful traceroutes would also be useful, but I haven't done this yet, as it's a little more involved.

It would probably be helpful to add support for hiding/showing the layer lines, and focusing on individual nodes and seeing only their routes--but those can be future additions.

Pull Request will be attached momentarily.

Preview: