* gnus-agent.el (gnus-agent-enable-expiration): New

	* gnus-agent.el (gnus-agent-enable-expiration): New
	variable. Either ENABLE or DISABLE.
	(gnus-agent-cat-set-property, gnus-agent-cat-defaccessor,
	gnus-agent-set-cat-groups): Provides abstract interface for
	accessing agent category.  Category now implemented by an alist.
	(gnus-agent-add-group, gnus-agent-remove-group,
	gnus-category-insert-line, gnus-category-edit-predicate,
	gnus-category-edit-score, gnus-category-edit-groups,
	gnus-category-copy, gnus-category-add, gnus-group-category): Use
	new agent category abstraction.
	(gnus-agent-find-parameter): New function. Search for agent
	configuration parameter first in the group's parameters, then its
	topics (if any), and then the group's category.  If not found
	anywhere, use the original defined constants.
	(gnus-agent-fetch-headers, gnus-agent-uncached-articles): Clearing
	gnus-agent-cache now blocks retrieving headers and articles from
	the local cache.  Fetched content is still added to the cache
	before being returned.
	(gnus-agent-fetch-session): Use error-message-string to generate
	displayed error message.
	(gnus-agent-customize-category): New Command. 'e' in category
	buffer opens category customization buffer.
	(gnus-category-write): Writes category file compatible with
	current, and previous, versions of gnus-agent.
	(gnus-category-make-function, gnus-category-make-function-1):
	Corrected documentation; parameter is predicate NOT category.
	(gnus-predicate-implies-unread): Now works in more cases per the
	todo comment.
	(gnus-agent-expire-group): Command now provides default of group
	under point.
	(gnus-agent-expire-group-1): Obeys new agent-enable-expiration and
	agent-days-until-old parameters.
	(gnus-agent-request-article): Now performs its own checks of
	gnus-agent, gnus-agent-cache, and gnus-plugged rather than
	assuming that the caller will do them correctly.
	(): Added one-time hook to gnus-group-prepare-hook.  Detects when
	gnus-agent-expire-days is set to an alist.  Converts said alist
	into group parameter so that gnus-agent-expire-days will not be
	needed.
	* gnus-art.el (gnus-request-article-this-buffer): Conditional
	checks surrounding gnus-agent-request-article removed; now
	performed by gnus-agent-request-article.
	* 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.
	* gnus-int.el (gnus-retrieve-headers,
	gnus-request-expire-articles): No longer checks gnus-agent-cache
	as it is handled internally by the agent.
	(gnus-request-head, gnus-request-body): Conditional checks
	surrounding gnus-agent-request-article removed; now performed by
	gnus-agent-request-article.

	* gnus-start.el (gnus-long-file-names): New function. Isolates platform dependent
	msdos-long-file-names.
	(gnus-save-startup-file-via-temp-buffer): New variable. Provides
	option of writing directly to file.  Avoids memory exhausted
	errors when .newsrc.eld is huge.
	(gnus-save-newsrc-file): Uses new
	gnus-save-startup-file-via-temp-buffer.
	(gnus-gnus-to-quick-newsrc-format): Rewritten to write to
	standard-output.
	(gnus-display-time-event-handler): Changed to alias from a defun
	to avoid a compile-time warning when display-time-event-handler is
	not defined.
	* gnus-util.el (gnus-with-output-to-file): New macro. Binds
	standard-output such that prin1 and princ will write directly to a
	file.

	* gnus.el (gnus-summary-high-undownloaded-face): Removed second bold keyword
	so that this face is actually bold.

	* nnkiboze.el (nnkiboze-request-art): Check gnus-use-cache before using cache.