As the title says, this commit is a massive overhaul.
I've rewritten/restrucuted almost everything in the controller scripts.
Because of that, there's a considerable possibility that I've broken
something somewhere.
Notable changes:
Added temporary uploads.
Removed file name length changer from dashboard,
in favor of an equivalent in homepage config tab.
This allows non-registered users to also set file name length.
A bunch of other undocmented stuff.
I don't know, I'm too tired to remember them all.