Unique namespace within a mount

[kamilsmtv]

Example:

$router->mount('/api/v1', function () use ($router) {
    $router->setNamespace('Source\Api\v1');
    $router->mount('/test', function () use ($router) {
        $router->setNamespace('Source\Api\v1\Test');
    });
});

[uvulpos]

LGTM if it works (did not test that yet), but please add some unit tests 😉 that would be icing on the cake 👍🏻

[kamilsmtv]

LGTM if it works (did not test that yet), but please add some unit tests 😉 that would be icing on the cake 👍🏻

75d5c6e