added/updated:
- additional comments
- replay_log function (logs mesg to event log instead of error log)
- get_net function (returns network addr given ip and mask)
- add_to_list and remove_from_list (adds and removes from basic unsorted
linked list)
- add_prefix (incomplete; adds prefix and interface based on network
statements)
- load_config (added code to parse network, router-id, and
passive-interface to router block processing of config file)