Fixes vote limiting by ID

Uses the `X-Forwarded-For` header to determine users' IP addresses, instead of naively using Heroku's internal IPs, so duplicate votes are now correctly prevented.

Fixes a bug that would cause a title to be un-votable by all users once a user who has voted for it reloads the page. (`var newTitle = title;` was creating a reference, but we needed a copy of the original title object.)

Makes some minor style improvements.

That's exactly what I did: https://github.com/cliss/accidentalbot/commit/070a265c2cd6b23f5570346fb59f83118b03ef16#diff-b39b1cc27d856a8bad2d0a327e4b3fe8R144