slaprunner: add screen component

software/slaprunner/common.cfg

 [buildout]
 extends =
   ../../component/bash/buildout.cfg
+  ../../component/busybox/buildout.cfg
   ../../component/cloud9/buildout.cfg
   ../../component/curl/buildout.cfg
   ../../component/dash/buildout.cfg
@@ -11,8 +12,8 @@ extends =
   ../../component/nginx/buildout.cfg
   ../../component/rsync/buildout.cfg
   ../../component/python-2.7/buildout.cfg
+  ../../component/screen/buildout.cfg
   ../../component/shellinabox/buildout.cfg
-  ../../component/busybox/buildout.cfg
   ../../component/vim/buildout.cfg
   ../../stack/flask.cfg
   ../../stack/shacache-client.cfg