Truncate path components according to filesystem limits

[lcorbasson]

Useful e.g. for MBID https://musicbrainz.org/release/05ffffa2-66d5-32a5-994b-9922b620c46d

Fixes #453 #565

[MerlijnWajer]

If I understand it correctly this changes the limits based on the full path inside the filesystem, is that right? Could you provide some example log files?

Also, I think the e variable with this change is overloaded with the exception handling, so there are cases where we log the file extension as the exception value I believe.