It turns out not a good idea to add z index support, it is very hard to do it right, so remove the logic to make it clear that we not doing this.
Add new api updateViewFrame, which only update view's frame but not rebuild the view tree, choose wisely when to use which.
Change on API fillView, now there is no offsetFrame param, that one will always be null for api client. Move the parameter to a internal method.
Add postProcess array, now one node can have multiple post processes, but there is no way to delete them now, if this is required, create a new node to replace this one. The node just a thin wrapper, it should be easy to do that.