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/cube/package.py

@@ -0,0 +1,55 @@
+# FIXME: Add copyright statement
+#
+from spack import *
+from contextlib import closing
+
+class Cube(Package):
+    """Cube the profile viewer for Score-P and Scalasca profiles. It 
+       displays a multi-dimensional performance space consisting 
+       of the dimensions (i) performance metric, (ii) call path, 
+       and (iii) system resource."""
+
+    homepage = "http://www.scalasca.org/software/cube-4.x/download.html"
+    url      = "http://apps.fz-juelich.de/scalasca/releases/cube/4.2/dist/cube-4.2.3.tar.gz"
+
+    version('4.2.3', '8f95b9531f5a8f8134f279c2767c9b20')
+
+    version('4.3TP1', 'a2090fbc7b2ba394bd5c09ba971e237f', 
+            url = 'http://apps.fz-juelich.de/scalasca/releases/cube/4.3/dist/cube-4.3-TP1.tar.gz')
+
+    # Using CC as C++ compiler provides quirky workaround for a Score-P build system attempt 
+    # to guess a matching C compiler when configuring scorep-score
+    backend_user_provided = """\
+CC=cc
+CXX=CC
+F77=f77
+FC=f90
+#CFLAGS=-fPIC
+#CXXFLAGS=-fPIC
+"""
+    frontend_user_provided = """\
+CC_FOR_BUILD=cc
+CXX_FOR_BUILD=CC
+F77_FOR_BUILD=f70
+FC_FOR_BUILD=f90
+"""
+
+    def install(self, spec, prefix):
+        # Use a custom compiler configuration, otherwise the score-p
+        # build system messes with spack's compiler settings.
+        # Create these three files in the build directory
+
+        with closing(open("vendor/common/build-config/platforms/platform-backend-user-provided", "w")) as backend_file:
+            backend_file.write(self.backend_user_provided)
+        with closing(open("vendor/common/build-config/platforms/platform-frontend-user-provided", "w")) as frontend_file:
+            frontend_file.write(self.frontend_user_provided)
+
+        configure_args = ["--prefix=%s" % prefix,
+                          "--with-custom-compilers",
+                          "--without-paraver", 
+                          "--without-gui"]
+
+        configure(*configure_args)
+
+        make(parallel=False)
+        make("install", parallel=False)