Tracked down a bug in twitsParser.ml of the off by 1 variety, caused bad output that served as input
for populartweets.ml; also corrected second off by one bug that was truncating tweet ids that prevented the
set of tweets from being augmented with additional datums (text, username, etc). Finally have some preliminary
output that looks promising. Run time is also reasonable but includes many false positives, which I'm sure
we can filter out now that we have candidate mappings from tweets to adhoc retweets and the like.