Add CACert Root certificate
CACert is a "community-driven certificate authority that issues free public key certificates to the public" (https://en.wikipedia.org/wiki/Cacert).
The root certificate of CACert (http://www.cacert.org/index.php?id=3) is used by many sites in the FLOSS community and is included in many GNU/Linux distributions (https://en.wikipedia.org/wiki/Cacert#Inclusion_status).
CACert is not included in the TBB.
It would be usefull to included this CA in the TBB, too.