Refactor boot process to allow for lack of wiki folder

Previously, the command line interface required a wiki folder to be
specified.

This is part of the work to enable TiddlyWiki5 to be used more easily
as a library in other node.js apps
Allow username to be set for the built-in server
Update some missed uses of the old type attribute of the list widget
Hack the list widget

Usually the list transcludes each tiddler through the sample template.
This hack makes it work differently, where each tiddler is used as a
template to render the same current tiddler. The attribute that
switches modes is called "hackTemplate" because this is a temporary
implementation of this capability for experimental purposes
Update the ViewTemplate to be driven by tag

Now the ViewTemplate just renders the current tiddler through each
template tagged `$:/tags/ViewTemplate`. This allows plugins (and users)
to add/remove elements from the ViewTemplate easily, without
overwriting the ViewTemplate itself.

(For @giffmex)
Readme update