PrivateFunction: prepareBrowserify
Adds the Browserify middleware the the given express.js app.

Parameters:
(Object) app - Express.JS app
(Object) options - Set of options
function prepareBrowserify(app, options) {
	if(!_.has(options, 'mainFile') || !_.has(options, 'url')) {
		throw new Error('Missing "mainFile" and "url" property.');
	}

	var mainFile = options.mainFile
		, url = options.url
		, exclude = options.exclude || []
		, browserifyOptions;

	exclude = exclude.concat(getServerOnlyFiles());
	browserifyOptions = { ignore: exclude };
	_.extend(browserifyOptions, _.omit(options, ['mainFile', 'exclude']));

	_.defaults(browserifyOptions, {
		debug: false
		, gzip: true
		, minify: true
	});

	app.get(url, browserify(mainFile, browserifyOptions));
}