Split opennet routing table into short links and long links (refactored)

This is similar to split-opennet-routing-table-original, which is better tested, but cleaned up history and with some minor opennet refactoring included. It does appear to work.
It seems like an enum would really help with the readability of calls to this function. It's not clear from the name what the argument means. IDEs help, but it should make sense without one too.

    public enum LinkType {
            SHORT,
            LONG,
    }