scripts/start-* replaced by src/gnome-shell

[Dan Winship <danw gnome org>]

The old scripts for starting gnome-shell are now gone and replaced by a
new script, src/gnome-shell (which will eventually be $bindir/gnome-shell)

The single gnome-shell script replaces both start-in-Xephyr and
start-replace:

    * if gnome-panel and metacity aren't running, then it starts
      gnome-shell in fullscreen mode

    * if gnome-panel and metacity are running, and you run
      "gnome-shell --replace", it behaves like the old start-replace
      script, first killing the panel and metacity, then running
      gnome-shell in fullscreen mode, and then restarting the panel and
      metacity again when you're done

    * if gnome-panel and metacity are running, and you don't use
      the "--replace" argument, then it behaves like the old
      start-in-Xephyr

Other than that, it takes the same arguments as the old scripts.

I'll update the wiki.

-- Dan