Comments about changes:

o Minor change: my compiler (gcc-2.95) complained about ct_debug so I 
inserted the classical DEBUGP macro.

o No important modifications in nfnetlink.c

o Added support to identify conntracks by id.

o Removed ordered list, now we just insert a unsigned int in struct 
ip_conntrack to hold the id. Now the table dumping is done iterating the 
hash table.

o Adaptation to ct-event API

o improved way to delete a conntrack (marcus sundberg)

o kill [dump|change]_natinfo, now that must be handle in 
[dump|change]_status.

o IMPORTANT: I haven't tested expectation handling.

Things I consider to do:

o split CTNL_MSG_GETCONNTRACK to two messages types: 
CTNL_MSG_GETCONNTRACK and CTNL_MSG_DMPCONNTRACK (dump)

o split CTNL_MSG_NEWCONNTRACK to two messages types: 
CTNL_MSG_NEWCONNTRACK and CTNL_MSG_UPDCONNTRACK (update)

o Move nfnetlink.h and nfnetlink_conntrack.h to netfilter/ directory.