Add angular-friendly menubar and provide sample navigation state to respond to menu actions

- Integrate file open dialog
- Give a sample of how to use $modal to open bootstrap 3 modals
- provide a few samples of how to manage navigation in the main window (with injected dependencies resolution)
- refactor home controller
- add app controller to handle all menubar actions. AppCtrl is always active, so no need to add event handlers in all views