muse-publish: Use narrow-to-region to fix various bugs.
* lisp/muse-publish.el (muse-publish-markup-tag): Code indent change.
(muse-publish-escape-specials): Use `narrow-to-region' so that we
better define the region to work with. Thanks to Sacha Chua for the
advice. Also make sure that we are more careful with the result from
next-single-property-change.
(muse-publish-surround-text): Use narrow-to-region. Make this routine
less brain-dead.
(muse-publish-verse-tag): Use narrow-to-region.
git-archimport-id: mwolson@gnu.org--2005/muse--main--1.0--patch-328