Disjointed chat histories and orphaned messages after a shared history file

[aThorp96]

This might belong on the server's repo, I can repost there if necessary.
If a client connects to two separate servers (not necessarily at the same time) and specifies the same history file, the user can reply to messages from another server. The new messages appear in the current chat history, and are viewable by anyone on the current server. The message, however, is an orphan.
Also replies to such a new message have the root as a parent ID.
I'm not sure if this is desired behavior or not.

[whereswaldon]

I think this needs careful thought. It is working as expected and intended right now, but I'm curious what we think should happen.

[whereswaldon]

This will be partly mitigated by automatically using different history files on different servers, which is implemented in #78