Avoid exposing users' IP addresses.

(Re-applying c11b6d from #5.)

We currently send the internal `title` data objects down to the client. They currently contains two fields that the client does not require: `titleLower` and `votesBy`, which has the list of IP addresses that voted for the title.

If we specifically select the fields we'd like to share with the client, it's a bit more verbose but we avoid the risk of accidentally exposing information we'd prefer to keep private.