add a new lifecycle event `Restoring` which is set when the editors/viewlets are being restored (start). also in the lifecycle service replace `onDidChangePhase` with `when`

rename startupTimer to performance, support mark and measure, drop promise support, add more marks to slowly phase out old timers

* 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