kwargs for embedded objects

It should be possible to propagate kwargs for embedded objects deeper down, even if the user doesn't supply the kwargs down into the dictionary of the containing object.
For example: when generating a project, we can give `analysis_kwargs` and that could contain a `simulator_kwargs`, but we should also be able to provide the `simulator_kwargs` directly to the project constructor and have that get copied into the correct object somehow.
I don't know if this can be automated or added manually in the beginning of each object.