Rewrite

I wanted to use this module for my own devices but had some problems with the coding. I rewrote most of it, except the ideas of [jk]probes. This code is probably not production ready (a lot of review is needed, I found a critical bug just today...), but at least most of new pieces are in place. This code should compile fine on old kernels (e.g. the sl5 one), but the retro-compatibility code is kind of ugly IMO.

New functionalities:
- Write to a dedicated device (still need some modifications to be linked to syslog-ng or rsyslog, but the ideas are in there)
- Use binary comparison instead of string comparisons for whitelisting 
- Whitelist stored in a single place in binary format, decodable into human-reading form with /proc/netlog-config
- Improve UDP tracking (enabled by default)

I do not think that this code should be merged as of now into your master branch, but by opening this merge request, we can start to discuss about those changes