* handle FreeDB server errors gracefully
In my repeated tests, I ended up upsetting freedb.org, which started
issuing 502 errors. Those errors are not correctly caught by the
program which just crashes with a backtrace. Instead, we handle those
like any other API error, which can already be generated by
perform_lookup (but not handled).
The visible result for the user is that the CD is simply not found on
FreeDB, an acceptable compromise, in my opinion.
Closes: #206
* harmonize an error message with other warnings
... which are all capitalized.
* freedb: Import from python-audio-tools 660ee2c
License: GPL-2.0+
* freedb: Remove unused code and set client name to whipper.
The removed functions depend on other classes of python-audio-tools,
but aren't needed here.
* cddb-py: replace with newer freedb implementation
The last release of cddb-py was 15 years ago. The freedb code taken
from python-audio-tools speaks protocol version 6 (Unicode) and is
compatible to both Python 2 and 3.
* freedb: Don't allow the pedantic CI test to fail
