switch CDDB implementation to freedb.py from python-audio-tools (#276)

* 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

whipper/common/program.py

@@ -31,6 +31,7 @@ import time
 from whipper.common import accurip, cache, checksum, common, mbngs, path
 from whipper.program import cdrdao, cdparanoia
 from whipper.image import image
+from whipper.extern import freedb
 from whipper.extern.task import task
 
 import logging
@@ -245,12 +246,10 @@ class Program:
         @rtype: str
         """
         # FIXME: convert to nonblocking?
-        import CDDB
         try:
-            code, md = CDDB.query(cddbdiscid)
-            logger.debug('CDDB query result: %r, %r', code, md)
-            if code == 200:
-                return md['title']
+            md = freedb.perform_lookup(cddbdiscid, 'freedb.freedb.org', 80)
+            logger.debug('CDDB query result: %r', md)
+            return [item['DTITLE'] for item in md if 'DTITLE' in item] or None
 
         except IOError as e:
             # FIXME: for some reason errno is a str ?