Unify root component

[Len]

Currently, the root component passed to init(...) has to return an array of the frame's properties and then the contained child nodes.
Instead, to define the frame's properties, hook_dom('', {...}); must be used and the root component returns only the child nodes just like a normal component.

This is of course super breaking so we need to increase the major version and update existing apps! (Will be easy though!)