Added backed audiotools to replaygain module and updated documentation
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
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