Function: preInitialize
This function is called before any initialization or constructor of the
<Barefoot.Router> is executed. It expects that the passed options object
contains the following elements:

app - An Express.JS app
layoutTemplate - The minimal HTML skeleton to render the application into.
Example: "<html><head></head><body></body></html>"
startExpressApp - A callback function which initiates the actual startup of
the Express.JS app from above.

Each of these are copied into this router object directly to access them
later on.

Parameters:
(Object) options
function preInitialize(options) {
	debug('pre initialize');

	this.app = options.app;
	this.layoutTemplate = options.layoutTemplate;
	this.startExpressApp = options.startExpressApp;
	this.apiAdapter = options.apiAdapter;
	this.setupRequestContext = options.setupRequestContext;
}