Users can now add the orignal Japanese/Korean etc artist upon uploading
and also edit it in edit.php. Only torrent groups that have 1 artist
are currently supported as otherwise users would need to manipulate some
sort of 2d array in upload.php. Currently searching is not setup.

* artist.php shows orig artist if it is present in the same way
torrents.php does for torrent groups.
* Updated all forms, including a note on only supporting orig artist for
single artist torrents as well as hiding the field when >1 artist is
bring added.
* artist/edit and takedit.php support orig artist.