Remove URL path from filenames

When files are imported into Omeka via CsvImport, the files need to be
accessible via the web, and, therefore, the filenames in Omeka are
an actual URL to the file as it was staged on the web for import.
Each filename was converted back to the simple filename by removing
the URL "path"
Change filename extension from .jpg to .tif

This is done because the files loaded into Omeka are jpg files,
but the original files from the imaging lab are tif files.
Note that the extension for files not generated by the imaging
lab were not changed since these file will not be stored in
Fedora, and therefore the associated metadata will not be used.