* Update definition of Promise in winjs.base.d.ts.

* Update to new Promise declaration

* Fix remaining errors.

Initialize extension host customers only after a connection has been established with the extension host; retire IThreadService

- Include extension specific properties only
- Refactor: Move extensions scanning to MainThreadExtensionService

- Enable / Disable actions show the current state
- Reload only when it is necessary and applied changes have impact.
- Blur the extension only when it is installed and not activated
- Improve messages for reload
- Remove status widget

* Use the extension descriptions available in the UI thread
* Don't wait for handling extension points until extension host is running
* Create the extension host process only after extension points have been handled
* Send the initial configuration as part of the initData to the extension host