note: i'm writing this after not working on this project for 6 months
so i'm kind of figuring this out for myself

anyway

Pylon: an outgoing connection from wilson to some chat server/service
	which could be "some irc server", "some xmpp server"
	or "discord" (discord is centralized so there's only 1 discord to connect to)
			(though you COULD have multiple Pylons for discord, if you were crazy)
		note that discord's concept of "server" aka "guild" is unrelated to anything

Channel: a particular chatroom on a particular service
	eg "#a on apionet irc" or "#general in some discord guild"
	in the code, a Channel is identified by a combination of a Pylon
		and a string 'channel descriptor', whose format depends on the Pylon type
	for instance xmpp channel descriptors are jids, discord uses numeric ids
	
Bus: a family of connected channels that messages will be bridged between

Message: you know what a message is. it has a bunch of fields, which are
	source_channel: the Channel the message came from
		maybe rename to source
	body: the string contents of the message
	sender: the username (on the source service) of the message's author
		TODO we need more info than that surely