upgrade to Awestruct 0.5.4.rc, yml syntax fixes

I've verified that Awestruct 0.5.4.rc properly renders AsciiDoc files. It also has some fixes that the integration branch currently in use does not.

The latest update to ispn.yml broke the parser because of a missing space. I also replaced empty values with a literal empty string in the Asciidoctor config to make the intent more clear.