fix #1035 do scraping tests on mock data

don’t store scraped pages with licensed lyrics in repo
nosetests: don't run slow tests by default
Added backed audiotools to replaygain module and updated documentation
Move script to download pages out of tests_lyrics.py

By default (as runned by CI tools), only *fake* example.com page is present in
rsr/lyrics and tests that check content of pages coming from *real* sources are
thus skipped.
Execute lyrics_download_samples.py to download pages from *real* sources. When
done and *real* pages are present on disk, no tests are skipped.
Move script to download pages out of tests_lyrics.py

By default (as runned by CI tools), only *fake* example.com page is present in
rsr/lyrics and tests that check content of pages coming from *real* sources are
thus skipped.
Execute lyrics_download_samples.py to download pages from *real* sources. When
done and *real* pages are present on disk, no tests are skipped.
fetchart: add 'sources' option

Fasten cover search by enabling engines selection and prioritisation.
remove comment
Fixed line lengths, typo in documentation.
Merge branch 'master' of https://github.com/sampsyo/beets

Conflicts:
	docs/plugins/replaygain.rst
Fix to documentation after merge of upstream repo
fetchart: import itunes only if necessary
fetchart: make test_art.py tests pass
fetchart: better document 'sources' option
fetchart docs: fix indent
fetchart: fix flake8
play: Log a message when no output is produced
Merge pull request #1070 from frubino/master

Added backed audiotools to replaygain module and updated documentation
Quiet down logging in #1070

This looks mostly helpful for debugging but redundant with the ordinary
logging.
Fix up docs, changelog for #1070
Fix ftintitle auto permanence (#485)

Oops. Plugins need to store to the database.