play: removing tmp file (changelog)
Remove prefix diff highlighting

This was well-intentioned but ended up being more confusing than it was worth.
It's always confused me when one digit gets un-highlighted in one of these
displays. The straw that broke the camel's back was when I got a "#1 -> #16"
change where the numeral "1" was un-highlighted. To fix this right would be
way more trouble than it's worth; I'm glad to be rid of this detail.

Conflicts:
	docs/changelog.rst
Malformed date queries no longer crash
Update embedart.rst
tox: add bs4 dependency 

bs4 is required by few test_lyrics.py tests
revert 0f5c2a4
add bs4 dependency

and reorder reps list alphabetically for readability
test_lyrics: add onelyrics.net source
lyrics: strip title excerpt before matching

improve the extraction of lyrics title from url title and increase the
matching threshold as a consequence.
add test to check lyrics title match in url title
fix building of lyrics file paths
fix flake8
lastgenre: add unit tests
lastgenre: use an ordinary Item instead of a Mock
fix flake8
Merge pull request #993 from KraYmer/lastgenre_coverage

Lastgenre coverage (mocking galore)
return no lyrics when HtmlParseError occured
skip test involving bs4 if python version too low
Add a displayable_path call in embedart (fix #995)
replaygain: More descriptive backend errors

This avoids a bare `except:` to catch specific errors and give better messages
when they fail. Should provide more insight to this trouble:
https://groups.google.com/d/msg/beets-users/6d-TOg0SuPY/iL39tmo3rqUJ

Also related to #874.

Feedback from @yevgenybezman or others more familiar with the backend would be
welcome.