Ensure that we replace zendframework/zend-router due to class conflicts

`zendframework/zend-mvc` in version less than 3.0 is still replacing `zendframework/zend-router` due to incompatible exception changes. Therefore we should tell projects that this package is replacing `zendframework/zend-router`.
The downsides are the mentioned exception incompatibilities but even if a user is requiring `zendframework/zend-router` in version 2 and using this package as well, he wont get the expected exceptions since `zendframework/zend-mvc` is being used instead of `zendframework/zend-router`.

Author: boesing

composer.json

@@ -45,6 +45,9 @@
         "phpunit/PHPUnit": "^4.5",
         "sebastian/version": "^1.0.4"
     },
+    "replace": {
+        "zendframework/zend-router": "^2.0"
+    },
     "suggest": {
         "zendframework/zend-authentication": "Zend\\Authentication component for Identity plugin",
         "zendframework/zend-config": "Zend\\Config component",