Fixed all compilation errors and warnings in traffic_navigation. If you committed these
abominations, I hope you're sorry. I only made things compile. If I fixed your code, it
might no longer do what you intended, but I can pretty much guarantee that it didn't do
what you intended anyway, so no complaining. Some undefined or implicitly defined
functions had no clear fix without writing new code, so I just added comments
recommending that the maintainers fix the problems. If that's you, I'd get on that.