Updated DJ to use fluent-ffmpeg 2.0.0-rc2.

Be sure to update fluent-ffmpeg to this version.
createTmpDir() now omits trailing slash.
Fixed artwork extraction function with new ffmpeg api.
Merge branch 'new-fluent-ffmpeg' into dev with updated fluent-ffmpeg.

Note: You must reinstall the fluent-ffmpeg@2.0.0-rc package at this point.