Added "ifempty" config to embedart plugin, re: issue 1020
Whoops, take two.
Slight style tweaks.
Whoops, trailing space. Take 2.
Seperated some code out from extract() into get_art(item). Cleaner and quicker way to check for embedded art.
Merge commit 'ca431b0' (part of #1033)

This is the part of PR #1033 that fixes #1020.
Minor fixes for #1033
Changelog/docs for #1033/#1020