Feature request: Logger shouldn't discard nonprintable characters

[vaclavbartos]

Currenlty, logger module (or rather unirec2csv functionality in Nemea-Framework) doesn't show non-printable characters in string-type fields. They are quietly discarded (see line 160). Similarly, new-line characters (\n) are converted to spaces (line 149).

I think this behavior is quite bad for debugging, as it hides a potentially important information (we're just dealing with a bug where there is \r at the end of some fields and it would help a lot if logger showed it).

I propose to print such characters using \x00 format or something silimar. (Maybe \u0000 if I remember correctly that string fields are expected to be in UTF-8 encoding?)

It needs some discussion though, as it's a change of behavior which can potentially break something (although I think it's not likely). And a corresponding change in logreplay may be necessary, if we want to keep that anything logged by logger can be replayed by logreplay.