Adds an import button to the transcode UI, allowing the user to pull in all files in a folder heirarchy to be transcoded.
Changed the transcode import tooltip and reimplemented using QDirIterator.
Renamed rootPath to just path, changed dialog message to reflect UI message.
Fixed formatting for merge.
Merge pull request #4521 from Korvox/master

Add an option to pull all music files recursively into transcoding