Readme update
Import the current prerelease of TiddlyWiki
Cleaning up

* Introduce wiki cascade for the config wiki so that the provided
tiddlers stay in an included wiki folder within the app bundle
* Renaming for clarity
More cleaning up
Remove obsolete code
Use TiddlyWiki's built in rendering support

The idea is that the main window will contain the config TiddlyWiki. It
will normally be hidden, but can be opened to inspect or update the
configuration.

We’ll add new methods for creating a window corresponding to a given
tiddler (which we’ll use for the wiki listing and the preferences
dialogue) and for creating a window corresponding to a TW file.