Trying to load keychain; trying to handle scenario where item is in the cache but not in the credentialManager

Rename Initialize(IView) to InitializeView; Change Subview.Initialize(IApplicationManager) to be virtual; Calling UpdateLog on HistoryView.Initialize(IApplicationManager)

# Conflicts:
#	src/UnityExtension/Assets/Editor/GitHub.Unity/UI/Window.cs

The history of the task system changes is at
https://github.com/shana/task-system (8b3880cd69)

Also get rid of the separate NPath provider for cleaner code