TweetAdder 4.1.150409

This is a REQUIRED update for all TweetAdder users.
-Added rate limits for following and unfollowing to help protect users and TweetAdder from possible Twitter suspensions due to following/unfollowing too fast
-Increased DM limit to 1000, per Twitter’s change in policy
-Optimized follow / unfollow actions to work more smoothly
-Fixed issue that would sometimes cause Follow Later list to take a long time to load
-Added option to the manage users screen to “Clear Old History”. This removes follow/follower data that is over 6 months old of users you are no longer following / followed by.
-Added image placeholder for tweets without images
-Added reminder that removing a license from the software does not affect the subscription status of the license.