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/atop/package.py

@@ -0,0 +1,16 @@
+from spack import *
+
+class Atop(Package):
+    """Atop is an ASCII full-screen performance monitor for Linux"""
+    homepage = "http://www.atoptool.nl/index.php"
+    url      = "http://www.atoptool.nl/download/atop-2.2-3.tar.gz"
+
+    version('2.2-3', '034dc1544f2ec4e4d2c739d320dc326d')
+
+    def install(self, spec, prefix):
+        make()
+        mkdirp(prefix.bin)
+        install("atop", join_path(prefix.bin, "atop"))
+        mkdirp(join_path(prefix.man, "man1"))
+        install(join_path("man", "atop.1"),
+        join_path(prefix.man, "man1", "atop.1"))