Detect HellaNZB log messages

Currently, LottaNZB is quite dumb and won't notice anything if there's something going wrong in HellaNZB, for example if the entered news server credentials are incorrect.

But it's crucial to detect what HellaNZB is actually doing and what didn't go right. That's why we need to detect certain log messages transfered over XMLRPC and probably also the ones put out by HellaNZB during startup (to know what was the reason for HellaNZB not to start).

This can be done using regular expressions created for every message we'd like to react to. This makes it also possible to extract certain information from the log messages. Every parsable HellaNZB log message needs an unique identifier, for example its own class.

What is to be done using this information isn't covered in this blueprint.