Add an option to delete from oldest to newest message

[dxdvostfr]

Atm the messages will only delete starting from the most recent one going to the least recent one. It would be great to have an option that allows us to reverse it. It would be useful to avoid getting seen by people snooping around recent messages and it would also allow us to keep chatting with people on a server while all of our old message history is getting deleted.