lyrics: add tests to track which websites can be scraped by our algo and be
used as sources fot the google custom search engine.
fix flake8
Update lyrics_sources.py

add copyright header
change chars replacements done by slugify()

adapt slugify() to make it return strings that can be used
as yaml keys (no spaces, etc.)
adapt is_page_candidate() accordingly
is_page_candidate() handle more languages

Add translations in spanish and german for tokens to
ignore when comparing an url title with a song title.
Move lyrics listings from .py to .yaml file
remove _lyricstext.py
add test_lastgenre.py
Move the filtering logic of '_tags_for' function into a dedicated 'filter_tags' function.
lastgenre: add tests functions
wip: rewrite setup_config
get rid of module level options variable

Conflicts:
	beetsplug/lastgenre/__init__.py
lastgenre: rewrite filtering logic to make tests pass

- remove filter_tags() as genres should not be removed this soon while
c14n has not been applied
- group all filtering logic in the function _resolve_genres (formerly
_strings_to_genre)
lastgenre: Restore min_weight option
Use self.config instead of global config
add a test that would fail with the restricted whitelist approach

If no option is set, valid genres should not be rejected. Which is an argument
to have a wide default whitelist.
add a test that would fail with the restricted whitelist approach

If no option is set, valid genres should not be rejected. Which is an argument
to have a wide default whitelist.
Allowing the whitelist to be disabled

By default it is disabled, setting the value to the empty
string will use the built-in whitelist (same behaviour than
c14n).
Canonicalization only return most common genre
Update _setup_config

Give an empty string to obtain default whitelist, None for no whitelist
or a stringlist for a custom one.