Fix another possible null dereference

I fixed the same bug for the daily stats and forgot to add the same check for
the weekly stats. Duh.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Enable rather simplistic authentication

http only, cleartext passwords, simple array to store users / passwords in the
source code. About as trivial (and easy to intercept) as it gets.

But using https requires a valid certificate and a strong certificate causes
effort and cost for the user... so this is better than nothing.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Merge pull request #59 from dirkhh/authentication

Authentication