guide/configure-cfengine/policy-framework.markdown: include up to Contributing
reference/promise-types/vars.markdown: add newline before code markup
reference/promise-types/vars.markdown: added some more data container tips
Merge pull request #680 from tzz/doc/containers

reference/promise-types/vars.markdown: added some more data container tips
guide/configure-cfengine/policy-framework.markdown: fix marker
Redmine#5986: document component classes