began a huge rewrite: select source first, then how to tag the files
still lots of stuff todo, but it already displays the existing tags of the uploaded file(s)
rewrite text that asks for file upload
manual tagger gathers a todo list, asks for first item
tagger processes the whole todo list now
add optional alias for tags
add a done/total status for the tagger
writing tags to file works for youtube m4a files now.
exiftool doesn't support writing to mp3s >_>
we'll need a workaround for that.
display tagging screen in a loop until user says import