[ADD] get_own_ifaces() to read local IP-Addreses
[ADD] assign_ips_to_nets() to match a list of IPs against the registered networks
[ADD] get_by_hostcode() get a srv-key by hostcode instead of srvid
[ADD] get_own_hostcode() to read /etc/hostcode
[ADD] build_srvid() ip to srvid
rewrote get_own_srvid() to support hostcode and several local ips
fixed usage of get_own_srvid()
[DOC] comments
print error messages to stderr