* Changes direct usages of GUI.enabled to instead use EditorGUI.BeginDisabledGroup() / EditorGUI.EndDisabledGroup()

Given that the repository object is created and managed by
the RepositoryManager, there's no reason to keep data in the
repository manager object. We can keep all the data in the repository
object and have it trigger events for data updates, while events
that are not directly related to data changes in the repository data
model are triggered directly from the repository manager.

This way, the manager manages things and the repository models things,
which feels like a nicer separation of duties.

The repository listens for events from the repository manager in order
to update its data, so the repository manager doesn't have to have a
reference to the repository (breaking the circular dependency)

Show branch name and url of the active remote.
Add tooltips.
Fix updating it when things change.

https://github.com/github-for-unity/Unity/pull/74

Use OnEnable/OnDisable instead of OnShow/OnHide, it's more consistent with Unity's
naming and our own window class.

AuthenticationView was missing some calls from the window, fixicate.

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