Merge branch 'mplegendre-multi_pkgsrc_roots' into develop

- This moves var/spack/packages to var/spack/repos/builtin/packages.

- Packages that did not exist in the source branch, or were changed in
  develop, were moved into var/spack/repos/builtin/packages as part of
  the integration.

Conflicts:
	lib/spack/spack/test/unit_install.py
	var/spack/repos/builtin/packages/clang/package.py

var/spack/repos/builtin/packages/py-astropy/package.py

@@ -0,0 +1,28 @@
+from spack import *
+
+class PyAstropy(Package):
+    """
+    The Astropy Project is a community effort to develop a single core
+    package for Astronomy in Python and foster interoperability between
+    Python astronomy packages.
+    """
+    homepage = 'http://www.astropy.org/'
+
+    version('1.1.post1', 'b52919f657a37d45cc45f5cb0f58c44d')
+
+    def url_for_version(self, version):
+        return 'https://pypi.python.org/packages/source/a/astropy/astropy-{0}.tar.gz'.format(version)
+
+    extends('python')
+
+    depends_on('cfitsio')
+    depends_on('expat')
+    depends_on('py-h5py')
+    depends_on('py-numpy')
+    depends_on('py-scipy')
+
+    def install(self, spec, prefix):
+        python('setup.py', 'build', '--use-system-cfitsio',
+                                    '--use-system-expat')
+        python('setup.py', 'install', '--prefix=' + prefix)
+