insin/substitute — Issue #1: previousTweet causing tweets to be re-examined
Author: insin
Created: 2012-01-24 02:31:10+00:00
State: open

If previousTweet is (legitimately) null, the most recent 20 tweets will be retrieved next run, even if they've already been examined. Keep a hold of enough previous tweet ids to ensure we have one to fall back on.