* visualizeroutes allows visualizing configured routes based on tielines and signal type
* can be filtered by source key, destination key, and type, along with partial matches for source & destination keys
* visualizecurrentroutes visualizes what Essentials says is currently routed by type
* uses same filtering as visualizeroutes
* improvements to how the routing algorithm works
Most devices that implement IRouting will now need to handle the possiblity of a null as the input selector, with the idea being that a null input selector should clear the route to whatever device is selected as the input selector. This may change to a typed value in the future.
