Map out ideas for the underlying data structure used for construction and introspection

[mjtamlyn]

[mjtamlyn]

I think we can write down the docs for the top part of the API if not the underlying pieces yet.

Roughly I was thinking:

{
    'adapt': [],
    'validate': [],
    'process': [],
    'render': [],
}

Naming is hard. We may want adapt_initial and adapt_new separate, or they could be nested. This is partly dependent on the API designs in #24