Added new .ini only variable **anon_redirect** with the default set to `http://derefer.me/?`

Added new .ini only variable **anon_redirect** with the default set to `http://derefer.me/?`.

> If users want to disable this they can go set the value to "" with SB shutdown.

What this does is prevents your local SB install from appearing in the backlink statistics of another web-page.
There are a whole bunch of link protection / anonymizers out there, just make sure you use the proper URL, it should end with a `?`, if you change the default.