Add README and DOAP file

README: Add a short README with basic information.

gnome-shell.doap: Add project information in DOAP format expected
  for GNOME projects.

http://bugzilla.gnome.org/show_bug.cgi?id=591564

README

@@ -0,0 +1,20 @@
+GNOME Shell provides core user interface functions for the GNOME 3 desktop,
+like switching to windows and launching applications. GNOME Shell takes
+advantage of the capabilities of modern graphics hardware and introduces
+innovative user interface concepts to provide a visually attractive and
+easy to use experience.
+
+For more information about GNOME Shell, including instructions on how
+to build GNOME Shell from source and how to get involved with the project,
+see:
+
+ http://live.gnome.org/GnomeShell
+
+Bugs should be reported at http://bugzilla.gnome.org against the 'gnome-shell'
+product.
+
+License
+=======
+GNOME Shell is distributed under the terms of the GNU General Public License,
+version 2 or later. See the COPYING file for details.
+