Code/ proposal: develop `accessifyhtml5.js` in parallel with a JSON Schema

[nfreear]

As part of Accessify-wiki I'm developing a JSON Schema - to allow fix-files authored in YAML format to be validated. Find it here,

• Github: nfreear/accessify-wiki ../schema/..schema.json
• http://json-schema.org

I'd like to propose some code edits for accessifyhtml5.js based on the Schema development, specifically:

• Some new allowed attributes - ATTR_SECURE:
  • target - for pop-up windows etc. target=NameNotBlank,
  • accesskey - still in HTML5 in spite of problems,
  • longdesc - http://w3.org/TR/html-longdesc
• A _CONFIG_ property within the YAML fixes containing meta-data,
• A _CONFIG_.ignore_defaults property