Restore getRoutes method
Restore getRoutes method

The `getRoutes` method has been removed as part of a [code cleanup[(https://github.com/laravel/lumen-framework/commit/82adca8e67269498387fd0090037e6c40821ef99).

As it was used by [some Lumen packages](https://github.com/appzcoder/lumen-route-list) is was used by some packages and as some people are [trying to understand why](http://stackoverflow.com/questions/34593573/how-to-get-routes-and-namespace-in-lumen-5-2) it has been removed this commit brings it back.
cnanney/lumen-framework,lasselehtinen/lumen-framework,laravel/lumen-framework,orchestral/lumen,crynobone/lumen-framework