muse-latex2png: Put png files in correct place. all: Introduce comment syntax.

muse-latex2png: Put png files in correct place.  all: Introduce comment syntax.

* experimental/muse-xml.el (muse-xml-markup-strings): Produce markup for
  'comment-begin and 'comment-end.

* lisp/muse-docbook.el (muse-docbook-markup-strings): Ditto.

* lisp/muse-html.el (muse-html-markup-strings): Ditto.

* lisp/muse-texinfo.el (muse-texinfo-markup-strings): Ditto.

* lisp/muse-latex.el (muse-latex-markup-strings): Ditto.  Remove second
  argument for "\ref", since it isn't valid LaTeX.

* lisp/muse-latex2png.el (muse-publish-latex-tag): Use
  muse-publishing-current-output-path rather than
  muse-publishing-current-file.

* lisp/muse-publish.el (muse-publishing-current-output-path): New
  variable that determines where the current file is being published to.
  (muse-publish-file): Set muse-publishing-current-output-path.
  (muse-publish-comments-p): New option that determines whether comments
  should be deleted or published.  Default is to delete.
  (muse-publish-markup-comment, muse-publish-comment-tag): Use
  muse-publish-comments-p.
git-archimport-id: mwolson@gnu.org--2005/muse--main--1.0--patch-261