attachOptions = function(parent) {

  var p = parent;

  // default configurations mixed with user config
  if (!p.config) p.config = utils.makeHashMap();

  // Never modify the imported config objects; instead, merge them
  // into a new object

  // attention! it is a tw-data-tiddler!
  p.config.sys = utils.merge(
    p.config.sys,
    utils.unflatten($tw.wiki.getTiddlerData(env.ref.sysUserConf))
  );

  // CAREFUL: Never merge directly into the default vis config object
  p.config.vis = utils.merge(
    {}, visConfig, utils.parseFieldData(env.ref.visUserConf)
  );

  // a shortcut for fields property
  if (!p.field) p.field = utils.makeHashMap();
  $tw.utils.extend(p.field, p.config.sys.field);

}
This function will append the global options to the tree. In case
this function is called again, only the option leafs are rebuild
so a process may safely store a reference to a branch of the option
tree as the reference doesn't change.

ATTENTION: For the path options, no trailing or double slashes!
This is NOT unix where paths are normalized (// is not rewritten to /).

@see
  - [TW5] Is there a designated place for TW plugins to store stuff in the dom?
    https://groups.google.com/forum/#!topic/tiddlywikidev/MZZ37XiVcvY
@param {object} parent The root where to insert the options into