fix(menu): Update active menu determination logic

This fixes too rxMenuItem matching too much if multiple items have a url containing, for example, `/accounts`.

![image](https://cloud.githubusercontent.com/assets/5025474/3881857/6699530a-2191-11e4-9e2c-fb15c94e6f85.png)

I love it, so I have no issues with it, just not sure about Kevin or
![image](https://cloud.githubusercontent.com/assets/1437154/3881974/b9d2d19e-2192-11e4-8964-8b9de9739bf9.png)