multi-line help

	.help will now display multi-line docstrings as several
	messages, one for each line, instead of concatenating them into
	a single long one.
	Those that consist of more than a certain number of lines
	(including the example for commands that have one) will be
	PRIVMSG'd to the asker instead of being posted into a channel.
	This number (3 by default) is configurable via the [help]/threshold attribute.
De-globalized threshold variable
Merge branch 'help_fix' of https://github.com/flashcactus/willie into help_fix