Integrated react-router

For #1 . Feel free to ask any questions. Decided against `react-router-bootstrap` in the end because it was never really finished, won't ever be and we can do without. `react-router` has a flexible and well-documented API:  https://github.com/rackt/react-router/tree/master/docs/api
maybe just integrate that route into 
\Koop\routes\index.ts instead will already make it clearer since I understood its meaning after reading that