More permalink tweaks

And more documentation this time!
Update the first rule of TiddlyWiki
Better defaults for radio widget

Now the “field” attribute defaults to “text”.
Use radio buttons in navigation settings

Radio buttons are much clearer
Add wiki.setText() method
Add first pass at select widget
Use the select widget in the various switchers
Docs update
Extraneous semi-colon
Standardise whitespace
Fix problem with tabs switching on language change

In 5.0.12-beta, if you change the current language setting then the
current sidebar tab setting is lost. This was because the qualified
title generated for the tabs was incorporating the current language
title, by virtue of a trick used in the PageTemplate to set the
“languageTitle” variable to a field of the current language plugin.
This trick left the current tiddler set to the current language, and
this current tiddler was still in force for the transclusion of the
page template segments.