* gnus-agent.el (gnus-agent-downloaded-article-face): New face,

* gnus-agent.el (gnus-agent-downloaded-article-face): New face,
used for showing which articles have been downloaded.
(gnus-agent-article-alist): Format change.  Add documentation.
(gnus-agent-summary-mode-map): New keybinding `J s' for fetching
process-marked articles.
(gnus-agent-summary-fetch-series): Command for `J s'.
(gnus-agent-synchronize-flags-server, gnus-agent-add-server): Use
gnus-message instead of message.
(gnus-agent-read-servers): Use file lib/methods instead of
lib/servers.  TODO: Why?
(gnus-summary-set-agent-mark): Adapt to new agent-alist format.
(gnus-agent-get-undownloaded-list): Remove articles that appear to
come from the agent.  This means that they are not downloaded.
TODO: Correct?
(gnus-agent-fetch-selected-article): Don't use history.
(gnus-agent-save-history, gnus-agent-enter-history)
(gnus-agent-article-in-history-p, gnus-agent-history-path):
Removed function; history is not used anymore.
(gnus-agent-fetch-articles): Fix handling of crossposted articles.
(gnus-agent-crosspost): TODO: What happened here?
(gnus-agent-check-overview-buffer): Some sanity checks on the
agent overview buffer.  This is a safety net used during
development.
(gnus-agent-flush-cache): The gnus-agent-article-alist format has
changed, write a number to the file indicating this.
(gnus-agent-fetch-headers): Rewrite to respect
gnus-agent-consider-all-articles without relying on the
`.fetched' files.  Make it fast.
(gnus-agent-braid-nov): Change resulting from
gnus-agent-fetch-headers change.
(gnus-agent-load-alist, gnus-agent-save-alist): Don't use
`.fetched' files.
(gnus-agent-read-agentview): New function, used by
gnus-agent-load-alist.
(gnus-agent-load-fetched-headers): Remove.
(gnus-agent-save-alist): Rewrite to accomodate new format.
(gnus-agent-fetch-group-1): Make sure list of articles is in the
same order as in gnus-newsgroup-headers.
(gnus-agent-expire): Document and implement extra args ARTICLES,
GROUP, FORCE.  Do not restrict usage.
(gnus-agent-uncached-articles): New function.
(gnus-agent-retrieve-headers): Use it.
(gnus-agent-regenerate-group): Rewrite.  TODO: Why?
(gnus-agent-regenerate): Ditto.  TODO: Why?

* gnus-start.el (gnus-make-ascending-articles-unread): New
function, for efficient mass-marking.

* gnus-sum.el (gnus-summary-highlight): Use new face for
downloaded articles.
(gnus-article-mark): Prefer to indicate read/unread status over
downloaded status.
(gnus-summary-highlight-line-0): New function, maybe rehighlights
line.
(gnus-summary-highlight-line): Use new face for downloaded
articles.
(gnus-summary-insert-old-articles): TODO: What does this change
do?