[WIP] Another MetroNavigationWindow Attempt

This time, I really want to fix #692. Implements #789.

### Screenshot2
#### First working build
![nav](https://f.cloud.github.com/assets/251501/1547041/279784c4-4d93-11e3-9874-406096cc6cd2.PNG)
![nav2](https://f.cloud.github.com/assets/251501/1547891/4f129460-4db3-11e3-931f-5ce02c5c38ba.PNG)