Add promise handles standard to the Policy Style Guid (Nick)
Merge pull request #328 from deb-cfengine/promise_handles

Add promise handles standard to the Policy Style Guide (Nick)
nth(): note that the second argument can be a position or a key now
reference/functions/format.markdown: explain %S
Updated Examples section, added new file, re-org
Merge pull request #329 from deb-cfengine/examples_org

Updated Examples section, added new file, re-org
reference/promise-types/meta: mention data containers can now be used.
Change to diff lexer for git-diff output
Move git diff command outside of diff output
Fixing indentation that breaks number sequence per Debs guidance
Document most important lexers and link to complete list