Support overriding welcome_screen?

[Zarel]

Currently, navigating to a SockJS server just displays Welcome to SockJS!

sockjs-node/lib/handlers.js

Lines 4 to 8 in e2369c3

	welcome_screen(req, res) {
	res.setHeader('Content-Type', 'text/plain; charset=UTF-8');
	res.writeHead(200);
	res.end('Welcome to SockJS!\n');
	},

It could be useful to override this with a custom message, such as a redirect to whatever webapp the SockJS server is a server for.

[Zarel]

So... is this a desirable feature? I could write it if there's interest.