Create a page to change layout for beta test

[Sebastian Böttger]

This page should show only a button and a short description. If the user has preset classic layout, the button enables the user to switch to BibSonomy 3 layout and vice versa.

To create this facility proceed as follows:

• use the URL '/bibsonomy3demo' and use the existing SettingsPageController
• create a separate view and jspx file

[Viktor Hemsen]

page incl. the button has been commited. as discussed, you can now add the layout + description