Make Muse installable and correct an Emacs21 issue.

Make Muse installable and correct an Emacs21 issue.

* Makefile (.PRECIOUS): Indicate that .info and .html files in this
  directory will be generated.
  (all): Compile muse.info by default.
  (doc): Refactor into individual generation rules for .html and .info
  files.
  (install): New rule that installs Muse source code, compiled .elc
  files, and the manual into proper places.

* Makefile.defs (ELISPDIR, INFODIR): Correct minor goof-up.

* README (Insinuation): Move old content of Installation here.
  (Installation): Fill out this section.
  (Further Documentation): Add link to my website and note that a full
  manual is included with Muse.

* lisp/Makefile (EL): Populate with .el files.
  (install): New rule that installs both .elc and .el files.

* lisp/muse-texinfo.el (muse-texinfo-info-generate): If we're running
  Emacs21, hack in a handler for the @documentencoding tag so that it
  doesn't error out.
git-archimport-id: mwolson@gnu.org--2005/muse--main--1.0--patch-67