* gnus-cus.el (gnus-agent-parameters): New variable. List of

	* gnus-cus.el (gnus-agent-parameters): New variable. List of
	customizable group/topic parameters that regulate the agent.
	(gnus-group-customize): Uses gnus-agent-parameters.  Replaced
	kill-buffer with gnus-kill-buffer to remove the killed buffer from
	the list of gnus buffers.
	(gnus-trim-whitespace): Removes leading and trailing whitespace
	from multiline strings.
	(gnus-agent-cat-prepare-category-field,
	gnus-agent-customize-category): Constructs a category
	customization buffer.