Recursive router

[ukayani]

• A router can now contain other routers; when you apply its routes, it recursively applies routes of the nested routers
• Added basic tests for this functionality

Addresses issue/enhancement #5

Usage

// routes/routes.js
router.add("/v1", require("./v1/routes"));

// routes/v1/routes.js
router.add("/auth", require("./auth"));

// routes/v1/auth.js
router.post("/register", function (req, res, next) {});

@Cyberuben @Steinweber

Please take a look at the tests under the describe block: Nested routers via .add and let me know if this fits your request.

If its good i'll merge it in. It doesn't break existing functionality.