Rework selected hops to be IP rather than hop based #7
Description
Currently when a hop is selected to show in the graph, it is selected by index (hop). When a route to the target changes, the hops can be different, extra hops, less hops, different IP, and this is not then graphed properly. For example, an extra hop appearing in the route with the last hop selected for rendering suddenly becomes not the last hop, so stops showing the new last hops latency.
Change hop selection to select based on IP address rather than hop index.
When drawing the graphs for a hop, if at a particular sample that IP is not available (because of a route change) simply plot it as a drop out.
That way, even if additional hops appear in the route, the last hop will still be plotted correctly, and route changes can be seen by the appearance and disappearance of hops (if they too are being plotted).