Fix losing message after server ping's IRC client

Make IRC client ping server if hasn't sent a packet for 30 seconds
(Xchat appears to do this). This works around the issue where the
first message sent the client after server PINGs it is lost.

Disabled some debug messages and added some more specific warnings.
Fix direct IRC conversations and show sent/received IRC chat

User to bot IRC conversations were not being reused, a new conversation
was started for each message.