Merge changes made in Gnus trunk.

Merge changes made in Gnus trunk.

gnus-sum.el (gnus-summary-mode): Don't make bidi-paragraph-direction bound in old Emacsen and XEmacsen.
gnus.el (gnus-group-find-parameter): Check for liveness of the buffer, not of the string which is its name.
gnus-sum.el (gnus-summary-move-article): Don't propagate marks to non-server-marks groups.
 (gnus-group-make-articles-read): Ditto.
gnus-srvr.el (gnus-server-prepare): Use it to avoid showing ephemeral methods (bug#9676).
gnus.el (gnus-method-ephemeral-p): New function.