Add new decoder for UDP port 5359 and a sample packet capture produced
on a couple of Linux hosts (a server and a client). Besides that, an
existing Babel capture contained AHCP packets and the current AHCP tests
cover 0, 1 and 2 "-v" flags.
All Babel intervals are encoded in centiseconds and must not be 0. In an
Update TLV the interval value 0xFFFF means infinity (RFC6126 Section
4.4.9). Update the test cases.
Babel sub-TLVs are a work in progress, a backward-compatible extension
to Babel version 2 protocol encoding. This update implements encoding
explained by Juliusz Chroboczek to decode ChanInfo sub-TLV of the Update
TLV.
