Clean up of logging messages as described here

All logging now prefers the ' (single quote) over the " (double quote)

https://github.com/sampsyo/beets/wiki/Hacking
Merge branch 'master' of https://github.com/sampsyo/beets
flake8 cleanup

Cleanup after cleanup
Fix Travis errors

I was over zealous on the brackets for formatting
Oh the formatting
Just go back to basics
displayable_path clean up error
Clean up of logging messages as described here

All logging now prefers the ' (single quote) over the " (double quote)

https://github.com/sampsyo/beets/wiki/Hacking
flake8 cleanup

Cleanup after cleanup
Fix Travis errors

I was over zealous on the brackets for formatting
Oh the formatting
Just go back to basics
displayable_path clean up error
clean up after rebase
Merge remote-tracking branch 'origin/master'

Conflicts:
	beets/importer.py
	beets/ui/commands.py
	beetsplug/lyrics.py
Merge pull request #909 from arogl/master

Clean up of logging messages as described here
Remove stray comment from #909

Yes, it is necessary.