* Rename libc.py to models.py
* Clean old unused libc.py code
* Make models top level importable
* Add State level model invocation function
So user is not required to pass in state at to a platform level func
* Explicitly mark what is in the public API
Protects against accidentally making something a public API just because
it has a docstring
* clean
* Move models.py to top level
* Rm models
* Fix docstring typo
* Add default param name, move comment
* Update docstring
