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/jdk/package.py

@@ -0,0 +1,46 @@
+#------------------------------------------------------------------------------
+# Author: Justin Too <too1@llnl.gov>
+#------------------------------------------------------------------------------
+import distutils
+from distutils import dir_util
+from subprocess import call
+
+import spack
+from spack import *
+import llnl.util.tty as tty
+
+class Jdk(Package):
+    """The Java Development Kit (JDK) released by Oracle Corporation
+       in the form of a binary product aimed at Java developers."""
+    homepage = "http://www.oracle.com/technetwork/java/javase/downloads/index.html"
+
+    version('8u25-linux-x64', 'e145c03a7edc845215092786bcfba77e',
+        url="http://download.oracle.com/otn-pub/java/jdk/8u25-b17/jdk-8u25-linux-x64.tar.gz")
+
+    # Oracle requires that you accept their License Agreement in order
+    # to access the Java packages in download.oracle.com. In order to
+    # automate this process, we need to utilize these additional curl
+    # commandline options.
+    #
+    # See http://stackoverflow.com/questions/10268583/how-to-automate-download-and-installation-of-java-jdk-on-linux
+    curl_options=[
+        '-j', # junk cookies
+        '-H', # specify required License Agreement cookie
+        'Cookie: oraclelicense=accept-securebackup-cookie']
+
+    def do_fetch(self):
+        # Add our custom curl commandline options
+        tty.msg(
+            "[Jdk] Adding required commandline options to curl " +
+            "before performing fetch: %s" %
+            (self.curl_options))
+
+        for option in self.curl_options:
+            spack.curl.add_default_arg(option)
+
+        # Now perform the actual fetch
+        super(Jdk, self).do_fetch()
+
+
+    def install(self, spec, prefix):
+        distutils.dir_util.copy_tree(".", prefix)