Initial python3 changes

Mostly just updating libraries, removing string encoding/decoding,
fixing some edge cases. No new functionality was added in this
commit.

lib/beetsplug/bareasc.py

@@ -0,0 +1,82 @@
+# This file is part of beets.
+# Copyright 2016, Philippe Mongeau.
+# Copyright 2021, Graham R. Cobb.
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and ascociated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# This module is adapted from Fuzzy in accordance to the licence of
+# that module
+
+"""Provides a bare-ASCII matching query."""
+
+
+from beets import ui
+from beets.ui import print_, decargs
+from beets.plugins import BeetsPlugin
+from beets.dbcore.query import StringFieldQuery
+from unidecode import unidecode
+
+
+class BareascQuery(StringFieldQuery):
+    """Compare items using bare ASCII, without accents etc."""
+    @classmethod
+    def string_match(cls, pattern, val):
+        """Convert both pattern and string to plain ASCII before matching.
+
+        If pattern is all lower case, also convert string to lower case so
+        match is also case insensitive
+        """
+        # smartcase
+        if pattern.islower():
+            val = val.lower()
+        pattern = unidecode(pattern)
+        val = unidecode(val)
+        return pattern in val
+
+
+class BareascPlugin(BeetsPlugin):
+    """Plugin to provide bare-ASCII option for beets matching."""
+    def __init__(self):
+        """Default prefix for selecting bare-ASCII matching is #."""
+        super().__init__()
+        self.config.add({
+            'prefix': '#',
+        })
+
+    def queries(self):
+        """Register bare-ASCII matching."""
+        prefix = self.config['prefix'].as_str()
+        return {prefix: BareascQuery}
+
+    def commands(self):
+        """Add bareasc command as unidecode version of 'list'."""
+        cmd = ui.Subcommand('bareasc',
+                            help='unidecode version of beet list command')
+        cmd.parser.usage += "\n" \
+            'Example: %prog -f \'$album: $title\' artist:beatles'
+        cmd.parser.add_all_common_options()
+        cmd.func = self.unidecode_list
+        return [cmd]
+
+    def unidecode_list(self, lib, opts, args):
+        """Emulate normal 'list' command but with unidecode output."""
+        query = decargs(args)
+        album = opts.album
+        # Copied from commands.py - list_items
+        if album:
+            for album in lib.albums(query):
+                bare = unidecode(str(album))
+                print_(bare)
+        else:
+            for item in lib.items(query):
+                bare = unidecode(str(item))
+                print_(bare)