Remove some dead code

Not sure when this code fell out of use, but it's no longer reachable.
Fixed layout of file upload & underlay

The file input sits above a button, but has opacity 0; its width and
position need to be aligned just right with the "select" button.
Justify nav tabs

(upgrade to Bootstrap 3)

The border rule needed extra specificity to override bootstrap's
defaults, presumably because CSS was designed by malevolent spirits.

The contents of the add panel have different heights for url and file
uploads.
[partial] more uploader work
[whitespace] tabs -> spaces
Add a missing semicolon
[partial] now I think the async processor works
Don't use poss in the auth tests

At the time they were written, you could GET /add without auth. Using
POST /add coupled the auth tests to the internals of the add logic,
though, so now that GET /add requires auth, we can decouple it!