Merge changes made in Gnus trunk.

Merge changes made in Gnus trunk.

nnmairix.el (nnmairix-request-set-mark, nnmairix-goto-original-article): Remove adding of article to registry, since `gnus-registry-add-group' isn't available anymore.
 (nnmairix-determine-original-group-from-registry): Use `gnus-registry-get-id-key' since `gnus-registry-fetch-groups' isn't available anymore.
gnus-spec.el (gnus-lrm-string): Use 8206 instead of ?\x200e to make things work in Emacs 22 and XEmacs, too.
gnus-sum.el (gnus-summary-from-or-to-or-newsgroups): LRM-ify the default From.
gnus-spec.el (gnus-lrm-string-p): New macro.
 (gnus-lrm-string): New constant.
 (gnus-summary-line-format-spec): LRM-ify the from.
 (gnus-tilde-max-form): LRM-ify string chopping.
gnus-ems.el (gnus-string-mark-left-to-right): New function.