[For 1.8] MyConversations: a conversation plugin for MyBB

[Laird]

Great - it seems that you have a clear and thorough understanding of the plugin and what could meaningfully be added in the future in this respect. Yes, a task to purge deleted messages would be a good addition, and I'm also thinking of checking when a member "deletes" a message (having its folder set to -1) whether all other participants have also "deleted" the message, and if so, deleting it from the DB at that point too.

DB deletion will probably not remove the associated row in the cnv_messages table entirely, only set its message field to NULL. This will be so that in the conversation view, message numbering does not change, and also so that, less importantly, also in conversation view, a "[Message deleted]" notice can be shown. (A couple of new columns will probably be added to support message deletion too, named something like deleted_by and deletion_datetime).

I've implemented the "on migration from PMs, assign folder = -1 for participants who deleted previously" functionality, but as it's such a small change, I won't release a new version (unless any other existing purchaser wants it immediately) - instead, I'll simply send you an updated archive privately.