Unambigious upload URIs

Still playing with Paperclip. Now we're using paths that include
http://csce.unl.edu/UNL-iLab because when we uploaded documents, they were
being placed in csce.unl.edu/UNL-iLab/UNL-iLab but downloaded from
csce.unl.edu/UNL-iLab. This hopefully will get Paperclip to use the correct
URL for both.