Fixes to the DT field type

Use the FEU username (optionally) so that we can track when a logged in user uploads a file

Add filetype capabilities to associate an icon with a particular upload. Also support an unknown file type for anything that does not match.

Completely re-worked the multiple database template stuff.

Adjustments to the default templates

Fixes to using category="all"

Generate thumbnails automatically (optionally) for certain file types, on upload, and on scan.