Add cram package.

var/spack/packages/cram/package.py

+from spack import *
+
+class Cram(Package):
+    """Cram runs many small MPI jobs inside one large MPI job."""
+    homepage = "https://github.com/scalability-llnl/cram"
+    url      = "http://github.com/scalability-llnl/cram/archive/v1.0.1.tar.gz"
+
+    version('1.0.1', 'c73711e945cf5dc603e44395f6647f5e')
+
+    depends_on("mpi")
+
+    def install(self, spec, prefix):
+        cmake(".", *std_cmake_args)
+        make()
+        make("install")