This cleans up the recwatch code to avoid some possible races. While you
were previously able to call Close more than once, this was really
something that would mask bugs, rather than a useful feature.
This splits the recursive watching bit of the file file resource into
it's own package. This also de-duplicates the configwatch code and puts
it into the same package. With these bits refactored, it was also easier
to clean up the error code in main.
