File fixes, stop list broadcast

This release brings in an option to disable the bot from displaying the entire keys list to the broadcast channel. It can be quite annoying if someone intentionally or mistakenly does a listing to get spammed if you have a large amount of keys. The option ListPMOnly will prevent this when set to true in the config file.

Also added protection around the file usage. Realized it was possible if people were fast enough to be able to do conflicting !add/!take/etc. This should take care of that