- Switch from the old 'log' class (ERR/DBG/etc) to a better
'logger' class. Also use LOG_* as defined in syslog.h.
- Make it possible to read debug messages even for release.
- Add a new argument (-v|--verbose) to 'ndppd' to change
verbosity level.
- Clean up some junk code that was left over.
- Replace ptr<> with strong_ptr<> and weak_ptr<> to easier distinguish
between weak and strong pointers.
- Fix a couple of bugs.