Merged from mwolson@gnu.org--2006-muse-el (patch 0-4)

Merged from mwolson@gnu.org--2006-muse-el (patch 0-4)

Patches applied:

 * mwolson@gnu.org--2006-muse-el/muse-el--devel--0--patch-2
   Added ability to show inline images in the Emacs buffer.

 * mwolson@gnu.org--2006-muse-el/muse-el--devel--0--patch-3
   Added enhanced list item insertion.

Detailed log:

(Author: Per B. Sederberg <per@med.upenn.edu>)

* lisp/muse-mode.el (muse-mode-map): Added new key binding to insert a
  list item.  New key mapping to toggle showing images.  Added a key
  mapping to insert a link to a file and modified the key map to insert a
  tag.
  (muse-on-blank-line): Helper function to determine if the point is on a
  line containing only blank spaces.
  (muse-insert-list-item): New interactive function to insert a new list
  item, taking into account the current list state.
  (muse-insert-relative-link-to-file): New function to insert a link to a
  file, relative to the default directory.

* lisp/muse-colors.el (muse-inline-relative-to): Added custom directory
  for where to search for images to inline in the buffer.
  (muse-colors-inline-images): Added custom boolean field for whether to
  show inline images in the buffer.
  (muse-colors-toggle-inline-images): New function to toggle showing the
  inline images in the buffer.
  (muse-unhighlight-region): Now removes end-glyph text properties to
  support XEmacs.
  (muse-colors-resolve-image-file): New function to determine if a link
  is an image and whether the version of Emacs can support inline images.
  (muse-make-file-glyph): New function to create an image glyph if we are
  using XEmacs.
  (muse-colors-insert-image): New function to insert an image in an Emacs
  buffer.
  (muse-colors-explicit-link): Modified function to have the ability to
  insert an image instead of formatting the text of the link.
git-archimport-id: mwolson@gnu.org--2006/muse--main--1.0--patch-26