Handle a few edge cases with project-page resolution gracefully.

Handle a few edge cases with project-page resolution gracefully.

* lisp/muse-project.el (muse-project-applicable-styles): Add assertion to
  make sure that PAGE is specified.  STYLES should be generated
  automatically, but it could theoretically fail.  I'm managing to
  trigger this when messing with unsaved Muse files.  Handle case where
  buffer has not yet been saved.
  (muse-project-find-file): Don't try to resolve relative links; just
  open them.

* lisp/muse-wiki.el (muse-wiki-resolve-project-page): Fix
  point-of-reference bug.  No need to call muse-project-page-of-file
  since buffer-file-name and muse-publishing-current-file both give us
  full paths.

* lisp/muse-mode.el (muse-link-at-point): For some reason,
  `skip-chars-backward' only respects the newline some of the time.
  Damned annoying.
git-archimport-id: mwolson@gnu.org--2005/muse--main--1.0--patch-118