Server & Client chat room

Features:

• Basic broadcast chat.
• User DMs, which are end to end encrypted using PKI.
• Seeing current online users upon login.
• Unique session ID and session passwords (user does not actually need to know their password or encryption keys).
• Graceful shutdown of the client notifies server, who notifies clients and ammends their online user list.

To add:

• Data validation to avoid throwing errors/exceptions.
• Specific client commands that can be echoed to the server, for example "!time", "!users" to request the current time from the server, or print the current list of online users.