Adding step to the build to retrieve user metadata. Apparently the user metadata that comes through from tweets in a stream is different than normal and doesn't contain the right set of data to properly linkify our descriptions. This should take care of that with just a small amount of overhead. Unless we're generating 18,000 user pages, we won't rate limit (Twitter allows 180 API calls per 15 minutes, but we can get 100 users per API call).