Document jsdoc

[vanillajonathan]

• The Sorter class in /jsdoc/lib/jsdoc/augment.js
• The Doclet class in /jsdoc/lib/jsdoc/src/parser.js
• The AstBuilder class in /jsdoc-parse/lib/ast-builder.js
• The Walker class in /jsdoc/src/walker.js

[klm127]

It'd be nice if we could publish jsdoc source code, documented with jsdoc, to a github pages here in the jsdoc repo.