Restructure projects.

Add interfaces and classes that implement them for navigation.
Restructure project.
Test ViewModel.

Test project.
WIP ReactiveShell
Remove CachedJournalEntry
Add ViewLoader and ViewCache. Add State object to JournalEntry.
TestApp and Suspension.

Fix interfaces. Implement ReactiveShell and View.
Initialize back and forward stack. Add missing ObserveOn.
Add Exit on Windows Phone. Add comments.
Add comments.
Move ISuspensionServiceExtensions.
Add exception handling.
Remove old ISuspensionHostExtensions.
Setup test app.
Fix WP8SuspensionService.
Update packages.
I'd like to se your internals.
Remove Refresh since I never seem to need it.
Add SemaphoreSubject from ReactiveUI.
Fix exceptions in navigation.
Add template for ReactiveShell.