NAT H.323 0.5 (beta) for Linux kernel 2.6.15 released

Change log:

1. Changed gkrouted_only default to 1 (Patrick McHardy)
2. Removed #ifndef offsetof in ASN.1 parser (Patrick McHardy)
3. Initialized datalen to 0 in ras_help to silence an incorrect gcc warning (Patrick McHardy)