Fix routing when application is started by Passenger and not by node

This fix solves the routing issue #19 when the application is started by Fusion Passenger. 
I've tested the suggested changes either starting the application with node and with Apache+Passenger.
```__dirname``` will point to the router.js folder, which is inside the node_modules folder. Removing the trailing path ```/node_modules/extdirect/lib``` gives us the application root folder.