Fix customization bugs concerning muse-project-alist.
* examples/johnw/muse-johnw.el: Update with latest version from John.
* muse-project.el (muse-project-alist-using-customize): New variable that
indicates whether or not we just used customize to modify the value of
muse-project-alist.
(muse-project-alist-get): Set muse-project-alist-using-customize.
(muse-project-alist-set): Only try to unescape muse-project-alist if
muse-project-alist-using-customize is set. Make sure that the value we
save to .emacs is unescaped.
(muse-project): Add definition for :value-delete so that we can work
around an Emacs21 and XEmacs21 annoyance.
git-archimport-id: mwolson@gnu.org--2005/muse--main--1.0--patch-244