Handle params with limiting regex

Routes can be defined with limiting regexes on the possible values
as follows

	app.get(''dogs', '/dogs/:size(big|small)', ...)

This is now handles correctly by the code

	var app = require('express')();
	require('express-reverse')(app);

	app.get('scary-dogs', '/scary-dogs/', function(req, res, next) {
		res.end('run away');
	});

	app.get('cute-dogs', '/cute-dogs/', function(req, res, next) {
		res.end('pick it up');
	});

	app.get('dogs-redirect', '/dogs/:size(big|small)', function(req, res, next) {
		if (req.params.size === 'small') {
			return res.redirectToRoute('cute-dogs');
		}
		if (req.params.size === 'big') {
			return res.redirectToRoute('scary-dogs');
		}
	});