apply Boundary changes to libdnet

 * merged fixes and features from nmap fork of libdnet-stripped
    https://github.com/nmap/nmap/tree/master/libdnet-stripped
 * merged fixes from https://code.google.com/p/libdnet/issues/list
 * mingw build compatiblity
 * added os_intf_name and pcap_intf_name attributes to intf.h for gaining access
   to the raw windows interface names
 * adds htonll/ntohll 64-bit endian conversions
updated README