Clearly define "users" and "developers"

[trevorhardy]

The existing code-base as "private" APIs (leading underscore) that indicate they are not for use by users (e.g. _raise_error_fast()). Who are the users and who are the developers in TESP? Using _raise_error_fast() as an example, is that something we wouldn't want somebody who is writing a new agent to have access to? Or are people who write agents definitionally not users but developers. If that's the case, what do users do? Do they use an API at all? As part of making TESP better in general we need to sort this out.