New, cleaner package repository structure.

Package repositories now look like this:

    top-level-dir/
        repo.yaml
        packages/
            libelf/
                package.py
            mpich/
                package.py
            ...

This leaves room at the top level for additional metadata, source,
per-repo configs, indexes, etc., and it makes it easy to see that
something is a spack repo (just look for repo.yaml and packages).

var/spack/repos/builtin/packages/cmake/package.py

@@ -0,0 +1,45 @@
+##############################################################################
+# Copyright (c) 2013, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://scalability-llnl.github.io/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License (as published by
+# the Free Software Foundation) version 2.1 dated February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+from spack import *
+
+class Cmake(Package):
+    """A cross-platform, open-source build system. CMake is a family of
+       tools designed to build, test and package software."""
+    homepage  = 'https://www.cmake.org'
+
+    version('2.8.10.2', '097278785da7182ec0aea8769d06860c',
+            url = 'http://www.cmake.org/files/v2.8/cmake-2.8.10.2.tar.gz')
+ 
+    version('3.0.2', 'db4c687a31444a929d2fdc36c4dfb95f',
+            url = 'http://www.cmake.org/files/v3.0/cmake-3.0.2.tar.gz')
+
+#    version('3.0.1', 'e2e05d84cb44a42f1371d9995631dcf5')
+#    version('3.0.0', '21a1c85e1a3b803c4b48e7ff915a863e')
+
+    def install(self, spec, prefix):
+        configure('--prefix='   + prefix,
+                  '--parallel=' + str(make_jobs))
+        make()
+        make('install')