Added packer component and a WIP software

component/packer/buildout.cfg

+[buildout]
+
+parts =
+  packer
+
+[packer]
+recipe = slapos.recipe.build
+
+# here, two %s are used, first one is for directory name (eg. x86_64), and second one is for filename (eg. x86-64).
+url_x86-64 = https://dl.bintray.com/mitchellh/packer/packer_0.7.5_linux_amd64.zip
+url_x86 = https://dl.bintray.com/mitchellh/packer/packer_0.7.5_linux_386.zip
+  
+# supported architectures md5sums
+md5sum_x86 = a545108a0ccfde7c1e74de6c4e6fdded
+md5sum_x86-64 = f343d709b84db494e8d6ec38259aa4a6
+
+# script to install.
+script =
+  location = %(location)r
+  self.failIfPathExists(location)
+  import sys
+  ARCH_DIR_MAP = { 'x86': 'x86', 'x86-64': 'x86_64' }
+  WK_SUFIX_MAP = { 'x86': '386', 'x86-64': 'amd64' }
+  platform = guessPlatform()
+  url = self.options['url_' + platform]
+  md5sum = self.options['md5sum_' + platform]
+  extract_dir = self.extract(self.download(url, md5sum))
+  shutil.move(extract_dir, location)

software/packer/software.cfg

+[buildout]
+
+extends = 
+  ../../stack/slapos.cfg
+  ../../component/qemu-kvm/buildout.cfg
+  ../../component/packer/buildout.cfg
+  
+parts +=
+  qemu
\ No newline at end of file