After I implemented message-generate-hashcash, it turned out that the
manual needed almost no changes.

Here is the changelog:

2004-11-14  Magnus Henoch  <mange@freemail.hu>

	* hashcash.el (hashcash-default-payment): Change default to 20
	(hashcash-default-accept-payment): Change default to 20
	(hashcash-process-alist): New variable
	(hashcash-generate-payment-async): Add
	(hashcash-already-paid-p): Add
	(hashcash-insert-payment): Don't generate payments twice
	(hashcash-insert-payment-async): Add
	(hashcash-insert-payment-async-2): Add
	(hashcash-cancel-async): Add
	(hashcash-wait-async): Add
	(hashcash-processes-running-p): Add
	(hashcash-wait-or-cancel): Add
	(mail-add-payment): New optional argument.  Conditionally start
	asynchronous calculation.
	(mail-add-payment-async): Add

	* message.el (message-send-mail): Wait for asynchronous hashcash
	results.  Don't clobber existing X-Hashcash headers.
	(message-setup-1): Call mail-add-payment-async when
	message-generate-hashcash is non-nil.

	* gnus.texi (Hashcash): New default value of
	hashcash-default-payment.
	
Magnus