Routing-related classes moved away from public classes into ToDoRouting inner classes.

Previous public classes contained minimal logic and were not re-used within the app, so it's better to have them as inner classes of ToDoRouting to minimize coupling between different files and also for reducing the number of Java files.
Merge pull request #876 from dprotti/privateroutingclasses

GWT - routing classes moved from public into ToDoRouting inner classes