code: function ignoreSubAst(node) {
          return node.type === 'CallExpression' && node.callee.type === 'MemberExpression' &&
              node.callee.object.type === 'Identifier' && node.callee.object.name === JALANGI_VAR &&
              node.callee.property.type === 'Identifier' && node.callee.property.name === 'I';
      }
docs: invoked by transformAst() to see if a sub-ast should be ignored.  For now,
  only ignoring calls to J$.I()