Rework route create

I've updated the route creating and editing to be a nicer experience.
Now there's an initial step where the player picks the destination, rather than clicking around the full edit dialog. The route is shown in white, and the camera moves to display it.

I had to revamp the camera systems a bit, as previously there was only the user controlled position, and focusing on an airport, with the only transition being moving back and forward between them. Now we also have and additional option, focusing on a route, and moving between any of the three options complicates things.