- routing header declaration with RFC3542 (note: sizeof(ip6_rthdr0) has changed!) also, sync up with RFC2460 routing header definition (no "strict" source routing mode any more) part of advanced API update (RFC2292 -> 3542).
(2) sync whitespaces, (3) update comments. (4) bring in some of portability and logging enhancements. no functional changes here.
NOTE: this branch (kame) is used just for refernce. this may not compile due to multiple reasons.