Add stack for node.js

stack/nodejs.cfg

+[buildout]
+extends =
+  ../component/lxml-python/buildout.cfg
+  ../component/nodejs/buildout.cfg
+  ../stack/shacache-client.cfg
+
+find-links +=
+    http://www.nexedi.org/static/packages/source/slapos.buildout/
+
+# Use only quite well working sites.
+allow-hosts =
+  *.nexedi.org
+  *.python.org
+  *.sourceforge.net
+  alastairs-place.net
+  dist.repoze.org
+  effbot.org
+  github.com
+  peak.telecommunity.com
+  psutil.googlecode.com
+  www.dabeaz.com
+
+parts =
+#  template
+  eggs
+#  instance-recipe-egg
+  nodejs
+  npm
+
+[eggs]
+recipe = zc.recipe.egg
+eggs =
+  ${lxml-python:egg}
+  slapos.cookbook