Some style fixes.
Fixes for skeletal meshes
 - Fixed creation of the bone entity network
 - Fixed offset of the root bone in animations
Changed identifiers for components and events to be URIs.
Prefabs support either the full uri, or just the name portion of a component uri. In the latter case they are resolved within the module and its dependencies (including engine, implicitly).
AssetManager is not longer a singleton, and is instead installed into the CoreRegistry. Tweaked load order to support this.
Various tweaks to serialization to support both the full uri, and resolution when given a partial uri (this keeps the changes backwards-compatible with existing saved games).
Snapshot of a roughly working JSON style applier thingy
And another step done
Add style states
Make UIButton compatible with new UI system