Allow multiple root CA certs.

Update root CA cert for cyphertite.com.

Since the SSL certificate for cyphertite.com recently changed, any
operating systems that don't have the root CA already available will
fail to download the initial individual user certs.  This commit
modifies the cert context handler to allow a list of root CA certs and
adds the new root cert.  This prevents the user from having to go
manually add a root CA before initial cyphertite configuration.