Pave the way for nested lists by adding markup strings.

Pave the way for nested lists by adding markup strings.

* examples/muse.rnc: muse.element.format is no longer a block, and may
  not contain muse.element.p.

* lisp/muse-latex.el (muse-latex-markup-strings): Add markup strings for
  '(begin|end)-(quote|uli|oli|dl)-item.  Add '(begin|end)-(dl|ddt|dde)
  markup strings.  This will allow for more flexibility in constructing
  all sorts of lists, especially definition lists.  Rename 'start-dde to
  'begin-dde for consistency.

* lisp/muse-texinfo.el (muse-latex-markup-strings): Ditto.
  (muse-texinfo-markup-regexps): Remove list concatenation regexp.

* lisp/muse-docbook.el (muse-docbook-markup-strings)
  (muse-docbook-markup-regexps): Ditto, but simplify paragraph regexp.

* lisp/muse-xml.el (muse-xml-markup-regexps, muse-xml-markup-strings):
  Ditto.

* lisp/muse-html.el (muse-html-markup-regexps, muse-html-markup-strings):
  Ditto.  Include <p></p> in center markup.
  (muse-html-markup-paragraph): Remove special treatment of blockquote
  and center.

* lisp/muse-groff.el (muse-groff-markup-strings): Rename 'begin-dde to
  'start-dde.

* lisp/muse-publish.el (muse-publish-markup-regexps): Begin implementing
  nested list preliminaries.  This is currently broken, probably.

* lisp/muse-regexps.el (muse-list-item-regexp): New regexp that matches
  the beginning of a list item.
git-archimport-id: mwolson@gnu.org--2005/muse--main--1.0--patch-325