Removed default implementation of Message, now all types that are used as messages must implement it explicitly (couldn't find a nice way to work around this :c )
Added a preprocessing step to messages, allowing them to initialise themselves using the current state before being handled
Chat and Kill messages now resolve the user/victim/killer SteamIDs in preprocessing
StateUpdater->Message,HandlerStruct->MessageHandler)Message, now all types that are used as messages must implement it explicitly (couldn't find a nice way to work around this :c )