* gnus-sum.el (gnus-summary-initial-limit): Inline
gnus-summary-limit-children.
(gnus-summary-initial-limit): Don't limit if
gnus-newsgroup-display is nil.
(gnus-summary-initial-limit): No, don't.
* gnus-util.el
(gnus-put-text-property-excluding-characters-with-faces): Inline
gnus-put-text-property.
* gnus-spec.el (gnus-default-format-specs): New variable.
* gnus-start.el (gnus-read-newsrc-file): Don't clear
gnus-format-specs.
(gnus-read-newsrc-el-file): Default to gnus-default-format-specs.
* gnus-spec.el (gnus-update-format-specifications): Really check
the Gnus version of the .newsrc.eld file.
(gnus-format-specs): Save the new default summary format.
* gnus-util.el (gnus-parent-id): Check whether references is empty
before splitting.
* gnus-sum.el (gnus-summary-from-or-to-or-newsgroups): Inline some
functions.
(gnus-gather-threads-by-references): Inline
`gnus-split-references'.
* gnus-spec.el (gnus-summary-line-format-spec): New, optimized
default value of gnus-summary-line-format-spec.