Messages might send multiple times in a row - have a check to delete all but the most recent

[extraludicinc]

https://stackoverflow.com/questions/38863125/slack-bot-using-botkit-to-clear-old-messages

Clear old messages, leaving only the most recent. Still unclear how often this should be done, could be on an interval or whenever a message is sent by the bot to check if there are previous messages still lingering