A low-level IRC message; this is an internal format for what actually goes over the wire.

	access
	arguments command prefix

	encoding
	asString

	private-initialization
	prefix:command:arguments:

	IRC commands	top
	quit

	access	top
	arguments return the arguments to the command
	command return the main command, in lowercase
	prefix return the prefix of the message, or nil if none

	encoding	top
	asString encode in the format used for transferral over the network

	private-initialization	top
	prefix:command:arguments:

	instance creation	top
	command:
	command:arguments:
	fromString: parse an IRC message from its network format
	prefix:command:arguments: