Bug: Passed the wrong OpenOption in writeTweets (was WRITE, should have been CREATE)
Bug: progress monitor doesn't remove tasks from old stages as it's moved to new (pending --> running --> completed)
BUG: constantly created a new list in every call to addToMultimap(), meaning we never stored more than one value per key.
IMPR: Add more logging when we choose not to download files for a user when updating.
BUG: We were constantly creating new files every time we wanted to write out the list of users tweets.