Add package for cask

Add a package for cask, the emacs project/dependency management tool.

Based on [Homebrew's formula][brew].

[brew]: https://github.com/Homebrew/homebrew-core/blob/master/Formula/cask.rb

var/spack/repos/builtin/packages/cask/package.py

@@ -0,0 +1,52 @@
+##############################################################################
+# Copyright (c) 2013-2016, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Created by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://github.com/llnl/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License (as
+# published by the Free Software Foundation) version 2.1, February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+#
+# Based on Homebrew's formula:
+# https://github.com/Homebrew/homebrew-core/blob/master/Formula/cask.rb
+#
+from spack import *
+from glob import glob
+
+class Cask(Package):
+    """Cask is a project management tool for Emacs Lisp to automate the package
+       development cycle; development, dependencies, testing, building,
+       packaging and more."""
+    homepage = "http://cask.readthedocs.io/en/latest/"
+    url      = "https://github.com/cask/cask/archive/v0.7.4.tar.gz"
+
+    version('0.7.4', 'c973a7db43bc980dd83759a5864a1260')
+
+    depends_on('emacs', type=nolink)
+
+    def install(self, spec, prefix):
+        mkdirp(prefix.bin)
+        install('bin/cask', prefix.bin)
+        install_tree('templates', join_path(prefix, 'templates'))
+        for el_file in glob("*.el"):
+            install(el_file, prefix)
+        for misc_file in ['COPYING', 'cask.png', 'README.md']:
+            install(misc_file, prefix)
+        # disable cask's automatic upgrading feature
+        touch(join_path(prefix, ".no-upgrade"))