function pdecode (str, hex) {
  return String.fromCharCode(parseInt(hex, 16))
}
Assign `setting` to `val`, or return `setting`'s value.

   app.set('foo', 'bar');
   app.set('foo');
   // => "bar"

Mounted servers inherit their parent server's settings.

@param {String} setting
@param {*} [val]
@return {Server} for chaining
@public