Inherit Layout from View, bind it to body instead of document. Rename methods.

 Renamed Layout methods and properties:
	* `_registeredRegions` to `globalRegions`
	* `registerRegion` to `registerGlobalRegion`
	* `registerRegion` to `registerGlobalRegions`
	* `unregisterRegion` to `unregisterGlobalRegions`
	* `unregisterRegions` to `unregisterGlobalRegions`

Removed layout events spec as it’s not needed because we have same view spec.

We had enough borrowed methods from View in Layout so just inheriting it will be cooler.