fetch_tweets_by_id is not logging invalid ids

[kerchner]

fetch_tweets_by_id should be logging ids that were not returned by statuses_lookup, but it is not.

The current fetch() method appears to assume that statuses_lookup throws and exception when any of the ids in the list passed to statuses_lookup are not found. However, this is not the case. statuses_lookup actually returns an array of JSON objects for only the found ids (it excludes any ids not found). So we will need to figure out which requested ids were not returned, and log those.

Recommend using get_status to look up the reason for each of the ids not found, and provide the reason in the log.