1) Fixes Ticket #208
2) Fixes Ticket #190
3) Fixes an unticketed issue where two items could collide when
creating the thumbnail and/or resize. For example, loading a.flv and
a.jpg would have generated the same thumbnail image. This change adds
a random value to the name to avoid conflicts.
4) Added item::__set() to clear the relative path if the name changes
does not provide a sort order. Separate the directory and files, sort
them individually and then merge them together so directories are at
the top of the list