Make a note in the configuration that import directory should not be "/files"

We configured the audio_import module so that it imports from files/. However, the problem with this is that the audio import page will show all the audio that was already imported into files/audio. Not only does this make things confusing and cluttered, but if you try to import audio that lives in files/audio, the audio module won't import it properly.

Audio import will give the following error message: "The following errors were encountered, preventing the ID3 tags from being saved:
filename set to non-existant file "files/audio/UYWI01EnviromentsForSpiritualGrowth.mp3" in getid3_writetags". Then when you look at the node it will say the audio filesize is 0 bytes.

I figured out that our staff was having problems with audio import because the audio had been uploaded to files/audio instead of just files, but it would be great if the subdirectories just didn't show up on the audio import screen, so this kind of thing wouldn't happen.

Alternatively, the audio import configuration screen could warn you not to use files/ as your import directory, but to use something totally unrelated to the Drupal filesystem. But we can't easily do that, since we've already committed to the directory structure we have now.

Anyway, thanks for all the work on this module. It is absolutely invaluable.