decode URL

This fix solves an issue I had when using a drupal module islandora_openseadragon.
when using 
```
/resolve?url_ver=Z39.88-2004&rft_id=http%3A%2F%2Fmemory.loc.gov%2Fgmd%2Fgmd433%2Fg4330%2Fg4330%2Fnp000066.jp2&svc_id=info:lanl-repo/svc/getRegion&svc_val_fmt=info:ofi/fmt:kev:mtx:jpeg2000&svc.format=image/jpeg&svc.level=1
```
the rft_id was not decoded...