- Default interval now 30 seconds (breaking!)
- Don't add default parameters to QR code (smaller)

Fixes #22

This involves temporarily decrypting all values being searched and
inserting them into a temporary table. Creation of this table can be
very slow when IP history is optionally searched. It might be better to
not make the temp table and just do the IP filtering from PHP.

Fixes #2

I swear one of these days I'll just do a search and replace all of them

Note that this requires a minor database migration of SiteOptions in
users_info and Paranoia in users_main

2FA class stolen from RobThree and stripped down.
Works best with qrencode utility installed, but will fall back to using
google charts if qrencode is missing.

For real though how was this even left broken like this? Did what.cd
just never use this feature or did they only half-port it to their
public repo?

Value added to source field contains the site name and a random string.
This change prevents uploaders from using self-generated torrent files
unless they also add the source value themselves. This value is provided
to them on the upload page, but is still more inconvenient than before.

Fixes #1